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L 3, 2 ' W '( ■ ■ ■ M k WOUSTRY 90 labor and material requirements K’ for sewer works rc oi construction the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C., 20402 - Price 30 cents For sale by P re fa ce T h is study o f total la bor and m a teria l requirem ents fo r the con struction o f sew er fa cilitie s is one in a s e rie s o f Bureau o f L a b or S tatistics studies o f variou s types of con stru ction that m ight be a ffected b y future gov ernm ental action. P re v io u s ly published studies exam ined the follow in g types of con stru ction: S ch ools, highways, F ed era l o ffice buildings, h osp ita ls, civ il w orks a ctivities o f the A rm y C orps of E ngineers, public housing, private o n e fa m ily dwelling units, and co lle g e student housing. The studies are being m ade by the B ureau 's D ivision o f P rod u ctivity M easurem ent, L loyd A . P rochnow , Chief, under the general d irection o f Leon G reen b erg, A ssistan t C om m ission er fo r P rod u ctivity and T ech n olog ica l D evelopm ents. T his bulletin was p rep a red tinder the su p ervision of Jam es F . W alker, by Roland V . M urray, who also was resp on sib le fo r com p ilin g the data for o n -site la b or requ irem en ts. C laiborne M . B all p rep a red the data on m a teria ls and o ff-s it e la bor requ irem en ts. The Bureau gratefully acknow ledges the coop era tion of o ffic ia ls o f the W ater Supply and P ollu tion C ontrol D ivision of the P ublic Health S erv ice, and o f the Com m unity F a c ilitie s A dm inistration of the Housing and Hom e Finance A gen cy in supplying p r o je c t p a yrolls on which m ost o f the o n -site requirem ents data w ere based. M r. P e te r P . Rowan, who was a sso cia te d with the P ublic Health S e rv ice , was p a rticu la rly helpful in this and related a re a s. iii CONTENTS Page Introduction ................................... .................................. ....................................... Nature o f survey ............................................................................................... G en eral survey f i n d i n g s ......... ............................................................................. P r o je c t c h a r a c t e r is t ic s ........................ O n -site m an-hour r e q u ir e m e n t s .............................. The co s t of d irect w a g e s ..................................... ................. ........................ R equirem ents by occupation ................................. ..................... ................... A ppren tice m an -h ou rs ....................................................................... ............... O vertim e m an -h ou rs .................................... .................................................... C onstruction t im e ...................... O ff-s ite e m p lo y m e n t ........... ............................................. ............................ C ost of m a teria ls u sed ........................................ .. P rev iou s studies ................................................... ................. .............................. Scope and m ethod o f s u r v e y ............................. .................................................. S a m p l e .................... .......................... ..................... ....................................... M an-hour estim ates .......................................... O n -site m a n -h o u r s ....................................... O ff-s it e m an -h ou rs .................................................................. 1 2 3 7 10 12 13 15 17 18 19 22 26 28 28 28 28 30 T a b le s : 1. 2. 3. 4. 5. A -l. O n -site la bor requ irem en ts fo r sew er w orks con stru ction , by se le cte d c h a r a c te r is tic s , 1 9 6 2 -6 3 .............................................. O n -site la bor requirem ents fo r sew er w orks con stru ction , by occupation and region , 1962-63 ................................................... P ercen tage distribution of o n -site m an -h ou rs fo r sew er line and plant con stru ction , by occupation and region , 1962-63 . . . M an-hour requirem ents per $ 1 ,0 0 0 of sew er con stru ction con tra ct, by producing se cto r and stage of m anufacture, 1962-63 ...................................................................................................... C ost o f m a teria ls per $ 1 ,0 0 0 of sew er w orks con stru ction con tra ct, by type o f m a teria ls, region , and type o f p ro je ct, 1962-63 ...................................................................................................... Number o f sam ple con tracts in selected ca teg ories . . . . . . . . . . . 11 14 16 20 24 29 C harts: 1. 2. D istribution of m an -h ou rs fo r each $ 1 ,0 0 0 o f sew er w orks con stru ction con tra ct. .............................................................. W here the sew er w orks con stru ction con tra ct d ollar g o e s ......... v 6 Introduction New con stru ction is a m a jo r com ponent o f the N ation 's output of goods and s e r v ic e s and an im portant s o u rce o f em ploym ent. Job s a re c r e ated not only at con stru ction sites but also in many m anufacturing, trade, s e rv ic e , and transportation in dustries w hich m ake, s e ll, and d eliver m a te r ia ls and equipment req u ired in con stru ction p r o c e s s e s . B ecau se o f its fa r reaching em ploym ent im pact, a vigorou s con stru ction industry is a significant aid in lim itin g unem ploym ent. T o provide factual data on the m o re d ire ct em ploym ent-gen erating effe cts o f con stru ction expenditures, the Bureau o f L abor Statistics (BLS) has a continuing p rogra m o f studies to m easu re labor and m a teria l r e q u ire m ents fo r variou s segm ents of the con stru ction industry. Construction o f sew er fa cilitie s w as s e le cte d as p a rticu la rly appropriate fo r study becau se o f the continuing F e d e ra l in terest and participation in w ater pollution con trol and the frequent prom in en ce of this type o f w ork in F ed eral em ploym ent generating p ro g ra m s. At the tim e to w hich this industry r e fe r s , 1962-1963, F ed era l a s s is t ance to lo c a l governm ents fo r sew er w ork s con stru ction took three fo r m s , im plem enting three different p u rp oses. One of these was the W ater P ollution C ontrol p rogram , dating fro m the m iddle 1950's, adm inistered b y the P ublic Health S ervice of the U .S . Departm ent of Health, Education, and W elfa re. This program p rov id es grants to lo ca l agen cies fo r partial financing o f co n struction o f sewage treatm ent fa cilitie s , including intercepting and outfall sew ers. The p rin cip al purpose is to provide an incentive to lo c a l com m unities to d e crea se the amount o f untreated w astes disch a rg ed to w ater s o u r c e s . The secon d continuing p rogram was the P ublic F a cilitie s Loan P ro g ra m under the Com m unity F a c ilitie s A dm inistration o f the Housing and Home Finance A gency. T his is a loan p rogram designed to a s s is t sm all com m un ities without estab lish ed c re d it rating to acqu ire needed public fa c ilitie s . Although loans w ere available fo r m any types o f fa c ilitie s , they w ere u sed p rim a rily fo r sew er and w ater w ork s. M o reov er, the sew er con stru ction tended to be fo r c o lle ctio n lines rather than treatm ent fa c ilitie s , thus com plem enting the pollution con trol p rogra m . The third p rogram was the A c ce le r a te d P ublic W orks P ro g ra m which w as aim ed at helping people livin g in e co n o m ica lly d istre s se d a rea s by providing im m ediate em ploym ent on public con stru ction . The p rogra m as a whole w as under the d irection of the A re a R edevelopm ent A dm inistration o f the U .S . Departm ent of C om m erce, but grants w e re m ade through agen cies already in the relevant fie ld s, such as the two m entioned p rev iou sly . Many different c la s s e s o f public w orks w ere approved tinder this p rogra m , but sew er fa c ilitie s , w hich accounted fo r ov er a quarter o f the total d ollar volum e o f ap provals, m ade up the la rg e st single group. Another rea son fo r the study is the cu rren t and p ro sp e ctiv e im p o r tance o f this w ork . Expenditures fo r sew er fa cilitie s con stru ction have r is e n steadily to a r e c o r d $1, 375 m illion in 1964. Although som e d e cre a s e o c c u r r e d in 1965 after the A c ce le r a te d P ublic W orks P r o g r a m 's initial im pact 2 of 1963 and 1964, expenditures are expected to continue to r is e . The needs to be m et a ris e not only from population growth and m obility, but also from d e ficien cies in existing waste d isp osal system s which are the subject of m uch cu rren t con cern . T hese d eficien cies are ch ie fly inadequate treatm ent of liquid w astes b efore their return to w aterw ays, and the existence of com bined storm and sanitary system s in m any urban areas which dump untreated w astes into w aterw ays during storm s. R em edy of the latter situation alone, by se p aration of storm and sanitary sew ers, would co st m any b illion s of d o lla rs . Nature o f Survey The study was designed p rim a rily to m easu re the total m an -h ou rs of labor requ ired for each $ 1, 000 of sew er fa cilitie s con stru ction con tra ct. T hese m an -h ou rs include both o n -site and o ff-s it e em ploym ent in the c o n struction industry, and the o ff-s it e em ploym ent in industries which produce and distribute the m a teria ls, supplies, and equipment used in the co n s tr u c tion. Data for o n -site labor include m an -h ou rs f o r su p ervisory, en g in eer ing, c le r ic a l, and custodial em ployees at the con stru ction sites, as w ell as those fo r w ork ers in the con stru ction tra d es. Data fo r o ff-s it e em ploym ent co v e r not only the final stage of m a teria ls m anufacture and transport to the site, but all other stages of production including the extraction of raw m a te ria ls. T hese labor requirem ents are thus the total of those generated by the con stru ction con tra ct. H ow ever, additional em ploym ent is generated by a con stru ction p r o je c t other than by the con stru ction con tract itse lf. This additional w ork includes preparation o f plans and sp ecifica tion s, in spection by governm ent a gen cies, installations by public utility em p loyees, and other appurtenant w ork . T hese other sou rces o f em ploym ent are not r e fle c te d in the estim a tes, w hich m ight differ slightly if total p r o je c t m an -h ou rs w ere related to total p r o je c t c o s ts . Em ploym ent crea ted by the respending and investing o f the w ages and p rofits a risin g from the co n stru ctio n --th e m u lti p lie r e f f e c t - - i s excluded. This study is based on data cov erin g con stru ction , ch ie fly in 1962 and 1963, on 138 sew er w orks con tra cts. Only new sanitary sew er fa c i li tie s are cov ered ; rep a ir w ork and w ork on storm drainage system s are excluded, although six con tra cts co v e r w ork on featu res o f com bined storm and sanitary system s. A ll of the p r o je c ts w ere under one or m o re o f the F ed eral assistan ce p rogra m s just d escrib ed : 85 w ere ad m inistered by the P ublic Health S erv ice and 53 by the Com m unity F a cilitie s A dm inistration. Thus, the study did not include any p ro je cts financed without F ed eral funds. Of the 138 con tra cts, 86 w ere p rim a rily fo r sew er line constru ction, and 52 p rim a rily fo r plant con stru ction . Data fo r these two groups are shown separately, w here c o n sid ered helpful, throughout the rep ort. 3 G eneral S urvey Findings C onstruction o f sew er w orks in 1962-63 req u ired an average o f 222 m an -h ou rs o f la b or fo r each $ 1, 000 o f con stru ction con tra ct amount. R equirem ents for other types o f con stru ction studied in this s e r ie s ranged fro m 204 to 236 m a n -h ou rs. E m ploym ent at the site o f w ork on sew er fa cilitie s req u ired 85 m an h ou rs, and o ff-s it e em ploym ent, p r im a r ily to produ ce the m a te ria ls used, req u ired 137 m a n -h ou rs. The total m an -h ou rs w e re distributed by industry groups as follow s: M an -hours per $ 1, 000 o f con stru ction con tra ct, 1962-63 Number T o t a l......................... O n -site con stru ction O ff-s ite , t o t a l............ C onstruction . . . . . M anufacturing . . . . T r a d e ....................... T ransportation . . . S e r v ic e s .................. Other ....................... P ercen t 222 85 137 7 73 23 11 7 16 100 38 62 3 33 11 5 3 7 M an-hour requirem ents in the two m a jo r types o f sew er w orks v a r ied only slightly. M an-hours per $ 1, 000 o f con stru ction con tra ct, 1962-63 L ines T o t a l .................... .. . O n -site con stru ction O ff-s ite , t o t a l . . . . . . Plants 223 86 137 221 83 138 T h ere w e re , h ow ever, som e d iffe re n ce s in the distribution o f these h ou rs, p a rticu la rly in the pattern o f o n -s ite con stru ction occu p ation s. T h ere w ere wide d iffe re n ce s in total o n -s ite m an -h ou r requ irem en ts am ong individ ual p r o je c ts , and a substantial d ifferen ce betw een p r o je c ts in the South and in the r e s t of the Nation. The study developed, as byproduct, a rough breakdown o f c o n t r a c t o r s ' c o s ts as betw een w ages paid to con stru ction w o r k e r s , m a te ria ls purchased, and overhead and p ro fit. The p ercen tages w e r e , r e sp e ctiv e ly , C h art 1. D istrib u tio n o f Man-Hours for E ach $ 1 0 0 0 of Sewer W orks C on stru ction C o n tract, 1 9 6 2 -6 3 Total Man-Hours: Total Man-Hours: 223 221 \ PRIMARY ► MAN-HOURS (168) m PRIMARY Off-site Construction MAN-HOURS (159) Transportation, Transportation, Trade, and Services Trade, and Services t t Last Manufacturing Stage Last Manufacturing Stage (or other processing) (or other processing) SECONDARY SECONDARY MAN-HOURS -► ◄ — MAN-HOURS ► (55) (62) Other Manufacturing Transportation, Trade, and Services Industries SEWER LINES UNITED STATES DEPARTMENT OF LABOR OF LABOR STATISTICS BUREAU SEWER PLANTS All Other Industries 5 25, 56, and 19 fo r all p r o je c ts c o v e re d . The w ages p ercen ta ges tended to be m o re un iform than the m an -h ou rs w orked, by p r o je c t and region , becau se high m an -h ou r requ irem en ts frequently w e re a sso cia te d with low w age ra tes and low m an -h ou r requ irem en ts with high wage ra te s. H ow ever, the p e r centage fo r plants w as somewhat higher than fo r lin e s — 27 and 24, r e s p e c tiv e ly , The m a teria ls ra tio s va ried little in total between the two types, 56 in lin es and 57 in plants. T here w e re , h ow ever, great d iffe re n ce s in the types o f m a teria ls used. The d ifferen ce between total con tra ct amounts and the com bined sum o f the w ages paid and m a teria ls purchased am ounted to 19 percen t o f the c o n tra ct am ounts. T h is residu al rep resen ts the total o f overhead and p ro fit. In this rep ort, overhead expenses a re those w hich cannot be d ire ctly attrib uted to s p e c ific p r o je c ts , as fo r exam ple, expenses fo r the cen tra l o ffic e and yard, in surance, and ta xes. In the y e a rs 1962-63, the average expenditures p er year fo r all types o f lo c a l public sew er fa cilitie s w ere $1 , 131 m illio n . T his study indicated that at this rate o f expenditure sew er con stru ction p rovid ed about 125, 000 fu ll tim e jo b s , 48, 000 o n -s ite and 77, 000 o f f - s i t e .1 Since fu ll-tim e w ork is the exception, e s p e c ia lly in heavy con stru ction , the actual num ber o f p erson s em ployed o n -s ite w as undoubtedly con sid e ra b ly g re a te r. 1 The fu ll-tim e w ork yea r fo r o n -s ite w ork is taken as 50 tim e s th average w orkw eek o f 3 9 .9 hours in 1962 and 40. 6 in 1963 a s re p o rte d in the B u reau 's em ploym ent and earnings s e r ie s . F o r other types o f em ploym ent 2, 000 hours w ere co n sid e re d a full y e a r 1s em ploym ent. C h art 2 . W here the Sewer W ork s C onstruction C o n tract D ollar Goes 1 9 6 2 -6 3 Stone, clay, glass products Supervisory, technical, clerical Skilled trades Semiskilled, unskilled 3.8 7.8 12.7 Stone, clay, glass products 6.2 Supervisory, 1.7 0.3 All other materials & supplies 2.6 technical, clerical 3.4 Skilled trades 15.0 Semiskilled, unskilled 8.2 UNITED STATES DEPARTMENT OF LABOR BUREAU OF LABOR STATISTICS 15.9 13.4 Electrical products SEWER PLANTS 4.8 All other materials & supplies 44.5 SEWER LINES 10.9 Metal products Sewer plant equipment 33.7 Metal products Sewer plant equipment Electrical products 4.2 7 P r o je c t C h a ra cteristics T o d a y 's urban s o cie ty uses a wide variety o f fa cilitie s fo r the c o l lection , treatm ent, and d isp osal o f human and industrial w astes. T hese fa cilitie s range from the sm all pipes co lle ctin g household w astes to the la rge trunk lin es and in tercep tors; fro m the sim ple sewage lagoon to the in tricate p r o c e s s in g com p lex o f the m etropolitan treatm ent plant; and fro m the "pack a ged" lift station to the m u ltim illio n -d o lla r pumping station. The curren t study included a ll of these fa cilitie s in sofar as they related to new sanitary sew er system s. R epair jo b s w ere excluded and also w ork on storm sew er sy stem s. S everal r e lie f sew er jo b s , featu res o f com bined storm and sanitary system s, w ere included. The 138 con tra cts 2 included in the study w ere distributed among types o f fa cilitie s as shown in the follow ing tabulation. (See appendix fo r additional details on sam ple selection and w eigh tin g.) C ontracts are divided into two b road c la s s e s , a ccord in g to whether they ch ie fly in volved pipeline o r plant con stru ction . A ctual (unweighted) con tra ct am ounts, 1962-63 Number o f con tracts Thousands o f d olla rs P e rce n t A ll c o n t r a c t s ....................... 138 $ 4 5 ,4 6 5 100 P rin cip a lly p ip e lin e s ................ L in es e x c lu s iv e ly .................. L in es and other (ch ie fly lift s ta tio n s )........................... P rin cip a lly p la n ts ...................... Sewage treatm ent plants . . . Pum ping station s.................... W aste stabilization ponds . . M i x e d ........................................ rr 86 24,717 15,932 3F 25 52 29 9 9 5 8, 785 20.748 14,493 3, 578 910 1, 767 19 46 32 8 2 4 54 2 B ecau se o f the d isp e rse d nature o f the w ork , " p r o je c t " and "c o tra ct" do not always have identical m eanings in sew er con stru ction . How ev er, in this rep ort, either w ord m ay be used to designate a single prim e general con tra ct (o r , ra re ly , a general and one or m o re sp ecia lty prim es) fo r con stru ction o f a sp ecified feature or group o f featu res o f a sew er system . 8 The 86 sew er line con tra cts w ere ch ie fly c o lle c tio n and trunk (or interceptor) lin es in about equal num bers; in addition, there w ere a r e la tiv ely sm all num ber o f outfall and r e lie f se w e rs. (Outfall sew ers conduct the effluent fro m the treatm ent plant to a r iv e r o r other disposal area; r e lie f sew ers in com bined storm and sanitary system s divert e x c e s s storm w aters d ire ctly into a r iv e r to prevent overload in g o f the treatm ent p la n t.) The pipelines p rim a rily w ere co n cre te , v itr ifie d -c la y , o r cast iron . Sm aller amounts o f steel, a sb e sto s-ce m e n t, and corru ga ted m etal pipe w ere used. In addition, one jo b used c a s t-in -p la c e r e in fo rc e d co n cre te pipe, and another used b r ic k m a son ry fo r lining a sew er con stru cted by tunneling. The "o th e r " elem ent in "lin es and oth er" in the previou s tabulation is alm ost en tirely lift stations. T hese are the pumping fa c ilitie s , usually sm all, req u ired in lin es w here the terra in is such that gravity alone w ill not insure adequate flow . In addition, o f co u rs e , all sew er lin es requ ire such structures as m a n -h oles and junction ch a m b ers, to facilitate the operation and m aintenance o f the lin es. T ren ch ing alm ost u n iversally was used fo r placing pipe below ground. H ow ever, in one entire jo b and in portions o f two oth ers, tunneling was used. T hese exam ples do not include the m any c a s e s w here re la tiv e ly short s e c tions o f the line had to be b o re d under such ob sta cle s as highways and ra ilro a d s. Of the 52 plants c o v e r e d in the survey, about half included som e external pipeline w ork, usually fo r in tercep tors or outfalls, in addition to the n e c e s s a r y w ithin-plant piping con n ection s. In each c a s e , h ow ever, the plant con stru ction predom inated. Seven of the treatm ent plants, represen tin g half o f the con tract amount in this ca teg ory , w ere to provide p rim a ry treatm ent o n ly --th e se p a r ation o f liquids and so lid s, with digestion o f the solid s, and disposal of liquids without further treatm ent. The other 22 plants p rovid ed s o -c a lle d secon da ry tr e a tm e n t--c o n v e rs io n o f the liquid w astes through b io lo g ica l p r o c e s s e s to com p aratively in offen sive effluents b e fo re their d isp osa l. E leven o f th ese, represen tin g a third of treatm ent plant con tra ct amount, u sed the activated sludge p r o c e s s , and 11, represen tin g a sixth o f con tra ct amount, used the other prin cip al p ro ce ss in g m ethod, the trick lin g filte r system . M ost treatm ent plants w ere o f sm all o r m oderate siz e , including s e v e ra l o f the sm all packaged equipment type, requiring hardly m o re o n -site con stru ction than fo r a foundation and a sh ell. H ow ever, 8 con tra cts o f over $ 5 00,000 each accounted fo r 70 p ercen t of the total con tra ct amount fo r treatm ent plant con stru ction . T hese la rg e con tra cts w e re fo r p r o c e s s in g com p lexes using a v a riety o f fa c ilitie s . M odern la r g e -s c a le sewage tre a t m ent con sists o f a s e rie s o f ph ysical, b io lo g ica l, and ch em ica l p r o c e s s e s and th erefore req u ires sev era l distinct types o f stru ctu res (tanks, lagoons, buildings, m ech an ical in sta lla tion s), and o f co u r s e , appurtenant piping, and e le c tr ic a l and other related w ork. 9 The pumping station ca teg ory was dom inated by a single v e ry large con tract fo r a plant which included installations fo r primping storm w ater as w ell as sanitary sew age. The other eight con tra cts w ere fo r rela tively sm all lift stations. W aste stabilization ponds are shallow ponds acting as natural sewage treatm ent "plan ts" through the action of m ic r o -o r g a n is m s on the raw sew age. They usually involve no m o re con stru ction w ork than excavation and diking, and inlet and outlet stru ctu res. Such ponds usually serve sm all com m uni t ie s --e a c h of the nine sam ple p r o je c ts was in a nonm etropolitan area. The five p r o je c ts designated as "m ix ed " in the previou s tabulation w ere con tracts with m ultiple fea tu res. The two la rg e st rep resen t com plete system s, with sew er lin es, lift stations, and treatm ent fa cilitie s . 10 O n-Site M an-Hour R equirem ents O n -site m an-hour requirem ents averaged 85 per $ 1, 000 3 of c o n tra ct amount of sew er fa cilitie s con stru ction but va ried w idely by p r o je c t c h a r a c te r is tic s . (See table 1.) Some o f the variations are consistent with those noted in previou s studies in this s e r ie s . A ch ief exam ple o f this is the con sisten tly higher em ploym ent generated by a dollar of con stru ction in the South com p a red with the rem ainder of the country. T o a sm a ller and le s s consistent extent, higher requirem ents also are evident fo r p r o je c ts outside o f m etropolitan a rea s, and sm a ller p r o je c ts . It usually is assum ed that the availability o f labor at com p aratively low hou rly rates in the South and in sm a ller com m unities redu ces the incentive fo r m echanization, and that sm a ller p ro je cts reduce the opportunity fo r it. The range in requirem ents fo r individual p r o je c ts w as ex trem ely w id e --fr o m 23 to 249 m an -h ou rs per $ 1,000 in sew er line p r o je c ts , and fro m 31 to 159 in plant p r o je c ts . In som e in stan ces, these wide ranges re fle cte d fin an cially v e ry p rofitab le, or virtu ally d isa strou s, jo b s as explained in the wage portion o f this study. T his is typical of h ig h -r is k operation s such as sew er fa cilitie s w ork. In other in stan ces, these wide ranges r e fle c t individual p r o je c t c h a r a c te ris tic s . H ow ever, the ranges ra d ica lly differ fo r the South and the r e s t of the country. M ost o f the con tract value of the sam ple fo r the South was in p r o je c ts with requirem ents over 100 m an -h ou rs per $ 1,000; fo r the rem ainder o f the country, m ost o f the value was in p ro je cts with requ irem en ts under 100. P e rce n t of con tra ct amount L ines South Plants Other U .S . South T o t a l ...................................... 100 100 100 Under 5 0 ...................................... 50 and under 1 0 0 ...................... 100 and Tinder 1 5 0 .................... 150 and under 200 .................... 200 and under 250 .................... 33 64 3 0 0 5 35 58 2 0 4 95 1 0 0 M an-hours per $ 1,000 15 4 Other U. S 3 The "m a n -h ou rs per $ 1, 000" con cept cannot be used fo r p rod u c ity com p a rison s becau se o f the different ph ysical quantities w hich the $ 1, 000 m ay rep resen t, owing to d ifferen ces in p r ic e s of con stru ction . P r ic e d iffe r en ces r e fle c t not only d iffe re n ce s in productivity, but a lso d iffe re n ce s in p ro fits, and c o sts o f m a te ria ls , la b or, etc. Table 1. On-Site Labor Requirements for Sewer Works Construction, by Selected Characteristics, 1962-63 M a n - h o u r s p e r $ 1 , 0 0 0 of c on tra ct C h aracteristics United State s N orth east N o rth Central South Wages as p e r c e n t of c on tra c t amount West United States N orth east N o rt h Central A v e r a g e h o u r l y earn ings South W est United State s N o rth east N o rt h Central South We st T o t a l , a l l c o n tra c ts . . . . . . 8 4.5 7 0 .8 66.6 1 0 9 .5 6 3.2 2 5 .3 25.5 2 4.6 26.3 2 3.8 $ 3 .00 $ 3 .60 $ 3 .70 $ 2 .41 $ 3.77 L in e s ................................ ................ P l a n t s ............................................... 85.9 8 2 .7 6 8 .6 7 2 .4 61.9 7 1 .9 117 .4 9 9.8 61.7 6 6 .1 2 4.3 2 6 .6 25.7 2 5 .3 23.8 25 .6 2 4 .5 2 3 .6 2 3 .5 2 4 .4 $ 2 .83 3 .2 2 $ 3 .75 3 .4 9 $ 3 .8 4 3. 56 $ 2 .09 2 .8 7 $ 3. b l 3. 70 A l l c o n tracts: M e t r o p o l i t a n a r e a .................. N o n m e t r o p o lit a n a r e a .......... ' 7 8.2 9 3 .1 7 0 .5 7 1 .2 6 3 .0 70.6 99 .4 1 2 2 .4 5 9 .6 69 .8 2 5.9 24. 5 25.4 25 .6 2 4 .2 25.1 2 8 .4 23.8 2 3.5 2 4 .4 3 .32 2 .63 3 .60 3 .5 9 3.84 3 .5 6 2 .8 5 1.94 3 .95 3 .5 0 L in e s : M e t r o p o l i t a n a r e a .................. N o nm etropolitan a re a . . . . . 74.7 1 0 3 .8 6 0.6 75.5 57.0 68. 1 9 8 .5 1 4 5 .5 5 8 .2 7 4.5 2 3 .0 26 .4 2 3.2 2 7.9 2 2 .2 25. 7 2 3.2 26.5 23. 1 25.3 3.08 2.5 4 3 .8 3 3 .6 9 3 .9 0 3. 78 2.36 1 .8 2 3.96 3.39 P l a n ts : M e t r o p o l i t a n a r e a ................. N o n m e t r o p o l i t a n a r e a .......... 83. 1 C2. 1 75. 1 64.4 70 . 7 73. 1 100. 7 9 8 .8 6 5.5 6 6 .4 30 .0 2 2 .6 26.4 2 1 .9 26. 7 24.5 35.8 2 1 .0 2 5.5 2 3.8 3 .6 1 2.75 3 .5 2 3 .4 0 3.7 8 3.36 3.56 2.13 3 .b 9 3.58 A l l con tra c ts : U n d e r $ 5 0 , 0 0 0 ......................... $ 5 0 , 0 0 0 - $ 9 9 , 999 .................. $ 100, 0 0 0 - $ 2 9 9 , 999 ............. $ 3 0 0 , 0 0 0 - $ 4 9 9 , 999 ............. $ 5 0 0 , 0 0 0 - $ 9 9 9 , 999 ............. $ 1 , 0 0 0 , 000 and o v e r .......... 9 2.0 94.8 95.8 8 4 .6 64. 7 84.9 7 7.6 52 .4 6 7.2 66. 1 65 .2 (l ) 8 3.4 71.8 75. 1 65.4 0 64.2 10 6 .4 131. 1 1 3 2 .8 1 0 7 .3 (>) 99 .6 (l ) 75. 7 67. 6 (*) 4 7.6 7 0 .0 2 5.7 26.1 25 .4 2 3 .2 21 .5 28 .4 2 7 .9 1 8 .4 2 5.2 2 1.9 2 5 .0 C) 2 6 .2 2 5 .6 2 8 .0 2 3.9 f1) 24 .4 2 4 .4 2 6 .6 24. 0 23. 2 t1) 30.8 0 28. 6 2 4 .3 l1) 18.6 26. 1 2. 79 2.76 2. 65 2. 74 3. 31 3.34 3.60 3.5 0 3. 75 3.31 3.8 4 3. 13 3 .56 3 .73 3 .6 6 (l ) 3 .8 0 2.29 2.03 1.8 1 2. 17 f1) 3.09 C) 3.77 3 .5 9 C) 3 .90 3.73 L in e s : U n d e r $ 5 0 , 0 0 0 ......................... $ 5 0 , 0 0 0 - $ 9 9 , 9 9 9 .................. $ 1 0 0 , 0 0 0 - $ 2 9 9 , 999 ............. $ 3 0 0 , 0 0 0 - $ 4 9 9 , 999 . . . . . . $ 5 0 0 , 0 0 0 - $ 9 9 9 , 999 ............. $ 1 , 0 0 0 , 000 and o v e r . . . . . 9 3.3 9 9.3 1 0 4 .1 88.4 5 5.4 8 1 .3 7 7.6 (') 66.5 64 .6 (!) (*) 84. 3 74. 1 71.8 62.4 o 1 2 7 .0 1 4 7 .1 1 2 3 .9 27 .5 26. 7 26. 7 2 3 .6 2 0.2 24.1 2 7.9 (*> 25.8 2 2 .6 (l) t1) 30 .0 27. 1 28 .4 23 .2 0 (*) C) 2 5 .9 2 6 .2 2 4.6 C) f1) (•) 29.9 25.7 (*) 16.3 <) ‘ 2.9 4 2.69 2.56 2.67 3.65 2.97 3.60 (*) 3. 77 3 .4 9 (!) (l ) (*) 78.4 73.1 <*) 4 1.7 (*) t1) 3 .5 6 3 .66 3 .9 5 3 .72 (') t1) 0) 2 .04 1 .7 8 1 .9 8 t1) (') (l ) 3 .8 1 3 .5 1 0) 3 .9 0 0 P l a n ts : Under $ 5 0 ,0 0 0 $ 5 0 , 0 0 0 - $ 9 9 , 999 .................. $ 100, 0 0 0 - $ 2 9 9 , 999 ............. $ 3 0 0 , 0 0 0 - $ 4 9 9 , 999 ............. $ 5 0 0 , 0 0 0 - $ 9 9 9 , 999 ............. $ 1 , 0 0 0 , 000 and over .......... 90. 7 83 .2 8 1.0 78.4 7 5 .2 8 7. 7 O (*) 64. 4 82.9 0 8 1 .1 0 0 (*) (‘ ) (*> 62.8 (*) C) C) 2 4 .0 24.6 2 3 .0 22 .5 2 2.8 31 .6 (*) (*) 2 3.9 (l ) (*) 0 2 3.5 C) 27 .4 (*) (*) 2 5 .5 24.4 (>) 19.0 2 1 .6 (’ ) C) (*) h 2 3.0 (*) (’ ) (*) 2.64 2 .9 6 2 .8 4 2. 88 3 .0 4 3.6 0 0) (l ) 3. 71 (l ) 2 .83 O 3.37 t1) 2 .5 1 f1) 1.90 2.49 0) C) t1) (l ) 3.67 (l ) (') 6b. 2 9 7 .2 (') 1 0 0 .2 86. 5 (*) (*) 1 Fewer than 3 contracts in category. (\) (l) C) (l ) C) (l ) (l ) h 3. 74 (l) t1) 12 The C ost o f D irect W ages W ages paid to o n -s ite con stru ction w o rk e rs constituted about 25 p e r cent of total con stru ction con tra ct amount, and this figure tended to be quite constant by region and other ch a r a c te ristic s (table 1). T his r e fle c ts a tend ency o b s e rv e d in p reviou s studies in this s e r ie s ; high m an-hour requirem ents tend to be a ssocia ted with low average h ou rly earnings and v ice v e rs a . F or exam ple, m an-hour requirem ents in the South are double those for the other region s fo r lin es con stru cted in nonm etropolitan a re a s, but average h ou rly earnings are alm ost on e-h a lf as m uch. The resu lt is a wage requirem ent differin g only slightly from the national av era ge. T his tendency o f variations in hours and rates to o ffse t one another is illu stra ted further in the follow ing tabulation, which shows that half of all the p r o je c ts (with som ewhat m o re than half o f the w eighted con tra ct amounts) have wage p ercen tages within 5 percentage points o f the national average. Plants Lines W ages as a p ercen t o f con tra ct amount Number of p r o je c ts studied T otal ................ .. Under 1 0 .................. 10 and under 20 . . . 20 and under 30 . . . 30 and under 40 . . . 40 and under 50 . . . 86 2 23 40 16 5 P e rce n t o f con tract amount 100.0 2 .5 30. 8 47. 2 15.8 3 .7 Number o f p r o je c ts studied 52 1 13 29 8 1 P e rce n t o f con tra ct amount 100.0 1.1 8 .7 6 1 .5 2 8 .4 .3 In addition to reflectin g p o ssib le d iffe re n ce s in productivity, the ex trem es in this table tend (sin ce con tract amounts a re fixed) to rep resen t unusually profitable o r unprofitable jo b s . The ex trem es m ay also r e fle c t la rg e d ifferen ces in percen tages o f m a te ria l c o sts in con tra ct am ounts, due to jo b c h a r a c te r is tic s . Sewer fa cilitie s con stru ction tends to be one o f the m o re speculative types o f con stru ction , ch ie fly becau se o f the b elow -g rou n d le v e l nature o f m uch o f the w ork . U nexpected encountering o f w ater m ay in cre a se co sts greatly by requ irin g extensive pumping; r o ck m ay req u ire d rillin g and blasting; unstable s o ils m ay req u ire heavy shoring. In the p r e s ent study, fie ld rep resen ta tives heard num erous com plaints o f lo s s e s on c o n tra cts in the cou rse o f data co lle ctio n , with unfavorable s o il conditions m ost com m on ly being blam ed. (The speculative nature o f sew er w ork contributed to one o f the ch ief p rob lem s encountered in data c o lle c tio n --th e difficulty o f obtaining in form ation on w ork p e rfo rm e d by p rim e and su b con tractors sin ce gone out o f b u sin ess. F our p r o je c ts in the sam ple studied w e re rep orted to have bankrupted the prim e c o n tra cto r s .) The portion o f table 1 showing average hou rly earnings illu stra tes the d iffe re n ce s in earnings between the South and the r e st o f the country 13 (p articu larly the W est), and between m etropolitan and nonm etropolitan a re a s . The extrem e range in this average in individual p r o je c ts was fro m $ 1.48 to $ 4 .7 4 for sew er line con stru ction and from $ 1.61 to $ 4 .3 1 fo r plants. The low er figure in each ca se rep resen ts a p ro je ct in a sm all southern com m unity; the la rg er figu re, a p ro je ct in a m etropolitan a r e a --o n e in the N ortheast and one in the W est. The w ages d iscu ssed in this section , and the average h ou rly earn ings based on them, rep resen t total g ro ss earnings, including overtim e p r e m ium s, b efore any deductions for s o cia l secu rity, health in surance, etc. The w ages do not rep resen t total la b or c o s ts , which would include tra v el and vacation allow an ces, co n tra cto rs' lega lly req u ired or voluntary contributions to health and w elfa re funds, and other frin ge ben efits. R equirem ents by Occupation The p rin cipal skilled trades requ ired in sew er fa cilitie s c o n s tru c tion are operating engineers and carpen ters (table 2). Operating engineers co v e r em ployees operating all types o f c o n struction m ach in ery except pow ered handtools (ja ck h a m m ers, d r ills , saws, and the lik e), the op e ra to rs of which are separately shown. F o r somewhat over a half o f all m an -h ou rs rep orted for operating en gin eers, the type o f equipment w as sp ecified . F ollow ing is a distribution o f these sp e cifie d m an hour s : P e rce n t T o t a l ................................................... B a ck h o e ..................................................... C r a n e -s h o v e l-d r a g lin e ......................... 100 16 19 D o z e r ............................................ T ra cto r (attachm ents, if any, not r e p o r t e d )................................................. 17 Pump and c o m p r e s s o r ......................... L o a d e r ....................................................... P ile d r i v e r .............................................. S crap er ..................................................... T re n ch e r, d it c h e r ................................. 13 12 8 3 3 A ll other ................................................... 4 5 P rim a rily , the equipment operated w as o f the type re q u ire d fo r trenching and other excavation, and backfillin g. P ile driving and pumping equipment w ere a ssocia ted with these o p e ra tio n s--th e fo r m e r w as exten sively used for installing sheet piling, and the latter fo r excavation dewatering. Table 2. O n-Site L abor Requirem ents fo r Sewer W orks C onstruction, by O ccupation and Region, 1962-63 United States O ccupation1 M an-hours P er per cent $ 1 ,0 0 0 T o t a l .................................... 8 4 .5 Superintendents and gen eral fo re m e n P ro fe s s io n a l and te c h n ic a l. C l e r i c a l ........... ....................... Northeast North Central M an-hours P er per cent $ 1,000 M an-hours P er p er cent $ 1 ,0 0 0 South West M an-hours P er p er cent $ 1 ,0 0 0 M an-hours P er per cent $ 1 ,0 0 0 100.0 70.8 100.0 6 6 .6 100.0 109.5 100.0 6 .8 .7 .6 8.1 -8 .8 6.1 .4 .7 8. 7 .6 1. 0 5 .6 ♦8 .2 8 .4 1 .2 .3 8 .3 1.0 1. 0 7 .6 .9 1.0 5 .7 .2 .2 9 .0 .3 .4 Operating e n g i n e e r s ............ 14.7 17.4 11.2 15.9 12.5 18.7 17.9 16.4 13.5 2 1 .3 C a r p e n t e r s ............................. P lu m b ers Iron w ork ers2 B rick la y e r s3 E lectricia n s .................... .. Cem ent fin ish e rs . . . . . . . . . P ain ters .................................. Other (skilled) trades4 . . . . 6 .5 2.1 1 .6 1 .4 1.3 1.1 .6 1 .2 7.7 2 .4 1.9 1.6 1.5 1.3 .7 1 .4 6. 8 3 .6 1.6 1.0 1 .6 .9 .6 1.1 9 .6 5 .0 2 .2 1 .4 2 .3 1 .2 .8 1.5 5 .5 2 .7 2 .4 1 .3 1 .5 1 .2 .6 1.0 8 .3 4 .0 3 .6 2 .0 2 .3 1.8 1.0 1.5 7.1 1 .3 1 .6 1.9 1 .3 1 .3 .5 1 .6 6 .5 1.2 1 .4 1.7 1.2 1.1 .5 1.5 6.1 1.7 .8 .5 .6 1. 0 .6 .8 9 .7 2 .7 1 .3 .8 1. 0 1 .6 1.0 1 .2 T ru ck d riv ers .................. .. O ile rs .............. H elpers and t e n d e r s ............ P ow er tool o p e ra to rs •. • •• 2 .7 2 .4 1 .5 1 .2 3 .2 2 .9 1.8 1 .4 3.1 3 .2 .3 .8 4 .4 4 .5 .4 1.2 1 .6 1. 7 1.0 .8 2 .5 2 .5 1.5 1.1 3.1 1.8 2.1 1.6 2 .9 1.7 1.9 1.5 2 .6 3 .9 1.8 1.1 4.1 6 .2 2 .9 1.8 L abor fo re m e n 1 .4 1.7 1 .3 1.8 1 .4 2.1 1 .6 1.5 1.1 1.7 5.1 3 1 .3 .2 6.1 3 7.0 .3 4 .0 22.2 .3 5 .6 31.3 .5 2 .0 22 .2 .6 3 .0 3 3 .4 .8 7 .8 4 6 .5 .1 7.1 4 2 .4 .1 4 .0 16.8 (5) 6 .4 26 .6 (5) P ip ela y e rs L a b o re rs ............................... F lagm en, w atchm en . . . . . . 1 2 3 4 6 3 .2 100.0 Skilled occu pation s include apprentices and working forem en . P r im a r ily re in forcin g iron w ork ers; also includes structural and ornam ental iron w ork ers. Includes m anhole b lock la y e r s . C ov ers p r im a r ily m ech an ics (construction equipment repair and p r o c e s s equipment installation) and m inor building tra d es. 5 L e ss than ♦05. Note: B ecause o f rounding, sums of individual item s m ay not equal totals. 15 C arpen ters w ere em ployed as exten sively in sew er plant co n s tr u c tion as in som e types o f building con stru ction p rev iou sly studied. T hey w ere em ployed p rim a rily for con crete form w ork on buildings and tanks. H ow ever, carp en ters w ere also em ployed to a significant extent in sew er line co n stru c tion for installing w ood shoring in tren ch es and building fo rm s fo r c a s t-in place con crete pipe and appurtenant con crete sew er stru ctu res such as m an h oles and outlet w ork s. R egion al d ifferen ces in the distribution o f m an -h ou rs by occupation should be in terpreted with caution. T hey resu lt fro m a variety o f fa cto r s , among w hich are the different prop ortion s of lin es and plants in the re g io n 's p r o je c ts , the chance o c cu rr e n c e of jo b s presenting unusual fea tu res, and lo c a l d ifferen ces in jo b c la s s ifica tio n . P erhaps the m ost striking variation, and one which has been ob serv ed in previou s studies in the s e r ie s , is the high prop ortion of com m on la b o r e rs in the South. T able 3, w hich shows the occupational distribution o f m an -h ou rs separately fo r sew er lin es and plants, illu stra tes the relative com p lexity o f the two types of con stru ction . The pattern fo r lin es r e fle c ts the com p aratively sim ple operations o f excavating, pipe handling, and backfillin g. Skilled con stru ction w o rk e rs account fo r only a quarter o f total m an -h ou rs, and these skilled w o rk e rs are ch ie fly operating en gin eers. On the other hand, com m on la b o r e rs alone account for 43 p ercen t of total o n -site m a n -h ou rs. T his ratio is far higher than the corresp on d in g ratios found in previou s studies in this s e r ie s . This fact m ight be a con sideration when assigning p r io r ity to p r o je c ts in program s fo r alleviating unem ploym ent. The occupational pattern for sew er plants r e fle c ts the greater and m o re va ried sk ills requ ired to constru ct the m any different types o f fa c ili ties in and around treatm ent and pumping plants. The skilled con stru ction trades account fo r n ea rly a half o f all o n -site m an -h ou rs, w h ereas com m on la b o r e rs account for only 30 percen t. T hese ratios approach those o b se rv e d in studies of building con stru ction . A ppren tice M an-H ours A p p ren tices in form a l, re g is te re d p rogra m s accounted for only 2 percen t o f the total m an -h ou rs w orked by the skilled production w o rk e rs on all sew er fa cilitie s p r o je c ts . The percentage fo r line con stru ction was m uch low er than that fo r plants, w here, as has been seen, there is a la rg e r p e r centage o f w ork ers in trades with strong apprenticeship tradition s. (National apprenticeship standards for heavy equipment op era tors and m ech a n ics w ere not establish ed until 1963.) T a b le 3, P e r c e n t a g e D istrib u tio n o f O n -S ite M a n -H o u rs f o r S ew er L in e and P la n t C o n s tru ctio n , b y O ccu p a tion and R e g io n , 1 9 6 2 -6 3 L in e s O c c u p a tio n 1 P la n ts U nited States N o rth east N o rth C e n tra l South 1 0 0 .0 1 0 0 .0 1 0 0 .0 1 0 0 .0 1 0 0 .0 1 0 0 .0 8 .6 .6 .4 8 .6 :3 .6 7 .0 .8 1. 2 7 .0 0 1. 2 7. 6 .5 .6 6 .1 1. 3 1 .8 9 .9 . 2 ( 2) 2 5 .6 16. 7 2 3 .8 14. 6 1 3 .0 1 2 .0 1 5 .8 1 6 .5 .9 .3 .8 .9 1 .3 .4 .2 1 .7 . 2 .3 . 1 8 .8 .6 .6 .5 .2 1 .3 ( 2) 14. 3 5. 1 3 .9 2 .0 3. 3 2. 3 1 .5 1 5 .9 8 .6 3 .8 2. 1 3 .9 2 .0 1 .4 1 5 .5 7. 6 6 .4 3 .0 4 .4 2. 8 1 .9 1 3 .9 2. 3 3. 2 1 .8 2. 7 2. 3 1. 1 1 1 .4 6 .9 2 .5 1 .2 2 .4 2 .1 2 .8 .6 .5 1 .4 2. 3 1 .6 2. 3 2 .9 .9 5. 2 5 .0 .4 .7 3. 7 3 .4 1 .8 1 .9 3 .6 1 .5 1. 7 .9 5 .5 7 .7 3 .0 1 .9 2.1 2 .5 1 .8 1 .7 3 .8 4. 2 .5 1 .5 1 .3 1 .7 1. 1 .5 1 .9 2 .0 2. 3 2. 3 1 .5 3. 3 2 .8 1 .7 1 .5 1 .3 1 .9 1 .5 1 .0 2 .0 2. 1 2 .4 1 .5 3.1 9 .6 42. 7 .4 1 2 .9 3 7 .4 1 .2 5. 8 3 8 .8 1 .7 10. 7 49. 2 ( 2) 7.1 2 7 .0 ( 2) .4 2 7 .0 ( 2) .3 28. 1 ( 2) 1 .9 32. 5 .3 4 .9 2 5 .9 (2) N orth C e n tra l U nited State s N o rth ea st T o ta l . ......................................... 1 0 0 .0 1 0 0 .0 1 0 0 .0 1 0 0 .0 S u p erin te n d e n ts and g e n e r a l . . f o r e m e n ....................................... P r o f e s s io n a l and t e c h n ic a l . . . C l e r i c a l ........................................... 8 .9 .8 .4 1 1 .0 1 .5 .7 9. 3 1 .8 .1 O p e ra tin g e n g i n e e r s .................... 1 9 .6 1 9 .9 C a r p e n t e r s ............................. P l u m b e r s .................................. I r o n w o r k e r s .................................... B r ic k la y e r s .................................... E l e c t r i c i a n s .................................... C e m e n t f i n i s h e r s ................. .. P a i n t e r s ........................................... 2 .4 .4 .4 1 .3 . 1 .5 (2) .7 O th er (s k ille d ) t r a d e s ................. .7 1 .4 T r u c k d r i v e r s ................. ................ O i l e r s ................................................ H e lp e r s and t e n d e r s .................... P o w e r t o o l o p e r a t o r s ................. 4. 1 3. 2 1 .8 1. 2 L a b o r f o r e m e n ............................. P i p e l a y e r s ................. .. L a b o r e r s ................. ................ .. F la g m e n and w a t c h m e n ............ 0 0 .6 0 0 .i 0 .7 0 South W est 1 .6 2 9 .9 . 1 1 S k ille d o c c u p a t io n s in clu d e a p p re n tice s and w o rk in g fo r e m e n . 2 L e s s than . 0 5 . N ote: B e c a u s e o f rou n d in g , su m s o f in dividu al ite m s m a y n ot equ al 100 p e r c e n t. W est 17 P ercen t of skilled trade man -h ou rs w orked by apprentices Total L ines Plants 2 .2 1.1 2 .9 Operating e n g in e e r s ............. ...................2 .4 0 1.5 8 .0 1.6 2.7 14.5 1.2 1.8 7. 1 All skilled t r a d e s ........... ____ ____ -----____ ____ 2.0 8 .9 1.4 1.5 ____ ____ 1.0 1.7 4 .6 18.9 0 0 8 .3 0 0 Other skilled t r a d e s ............. ____ 5 .2 .4 C a r p e n t e r s ...................... .. . . . P l u m b e r s ................................. Iron w o rk e rs . •. . .................. B r i c k l a y e r s ............................. E l e c t r i c i a n s ......... .. Cement fin is h e r s ........... * . . • P a i n t e r s ........... ........................ In the aggregate or in percentage of total, apprentice m an -h ou rs w ere significant ch iefly in the plum bing and e le c tr ic a l tra d es. O vertim e M an-H ours F o r 102 (o f the 138) p r o je c ts , w hich accounted fo r o v e r 80 percent o f the total m an -h ou rs w orked in the sam ple p r o je c ts , data w ere available fo r m easurin g the prop ortion o f these hours w hich w ere paid fo r at overtim e ra te s. F or all p r o je c ts , this amounted to 7 .5 percen t. The ratio fo r sew er line constru ction, h ow ever, was m uch higher than fo r plant con stru ction , 10. 3 and 4. 2 re sp e ctiv e ly . On severa l sizable line p r o je c ts , this proportion approached a quarter of all hours w orked. The higher proportion of overtim e hours on line con stru ction p rob a bly is due to the m ore exposed conditions under w hich this w ork is done and to the loca tion of the w ork on public r ig h ts -o f-w a y . Both these conditions requ ire intensive activity when w eather conditions are favorable (p a rticu la r ly to make m axim um use of heavy con stru ction equipment) and when tra ffic w ill be disrupted the lea st. 18 C onstruction T im e On the average, the jo b s co v e re d in this survey requ ired a little o v er 33 w eeks to com p lete. The sewage plants, h ow ever, req u ired a sub stantially lon ger p eriod for con stru ction than the lin e s --4 1 weeks as c o m pared with 28. The d ifferen ce was not due to variations in the distribution o f the p r o je c ts , fo r exam ple by c o s t c la s s . The relation sh ip held fo r all size s and loca tion s o f p r o je c ts ; on the average, sew er plant con stru ction req u ires about 50 p ercen t lon ger than com p arable sew er line p r o je c ts . T hese figu res c o v e r the total elapsed tim e fro m the start of site operation s to the substantial com p letion of the con tra ct. T hey do not include the som etim es extensive p eriod o f testing and rem ed ial w ork, but they do include p eriod s during the co u rs e of con stru ction when, fo r variou s re a so n s, no w ork was p e rfo rm ed . T o m easu re the distribution o f em ploym ent o v er the p e rio d o f c o n struction, the con stru ction tim e fo r each p r o je c t was divided into 10 equal in tervals, and data w ere tabulated on the number o f m an -h ou rs w orked in each in terval. T his p roced u re perm itted the com bination o f m an -h ou rs fo r p ro je cts o f variou s s iz e s in o rd e r to obtain typical em ploym ent patterns. The resu lts fo r the two m a jo r groups o f p r o je c ts re v e a le d little d ifferen ce in the tim ing o f em ploym ent: Tenths o f con stru ction p e riod T otal P e rce n t o f m an -h ou rs: Sewer lin es ................ Sewer p la n t s ................ 1 2 3 4 5 6 7 8 9 10 100 100 5 5 10 10 13 13 15 14 14 13 13 13 11 11 8 10 7 7 4 4 19 O ff-S ite Em ploym ent F o r each m an-hour o f w ork p e rfo rm e d at the con stru ction site of sew er fa cilitie s con stru ction , an additional 1 .6 m an -h ou rs o f w ork w ere req u ired elsew h ere to produ ce and distribute the m a te ria ls, supplies, and equipment used at the site. The ratio was about the sam e fo r lin es and plants. T hese are rather high ra tios com p a red with the sam e ratio in other types o f con stru ction . T his resu lts in part fro m the fact that site w o rk e rs are able to place rela tiv ely la rge values o f w ork p er hour on this kind o f c o n s tr u ctio n --in the ca se o f lin es, by the use o f heavy con stru ction equip m ent; in plants, by the installation o f p r o c e s s equipm ent. T his o ff-s it e activity d irectly a ffects a substantial num ber o f indus t r ie s ; in d irectly it a ffects virtu ally all industries as the im pact o f the initial pu rchases spreads throughout the econ om y. T hese e ffe cts are shown in table 4, w hich p resen ts by industry the total m an-hour requ irem en ts fo r sew er w ork s con stru ction . P rim a ry m an -h ou rs a re defined as those w orked at the con stru ction site and in activities c lo s e ly related to the site: o ff-s it e em ploym ent in the con stru ction industry, em ploym ent in the la st stage o f m a teria ls m anufacture, and em ploym ent in the in dustries distributing the final product to the site. S econdary m an-hours are those req u ired p r io r to final m anufacture in all a ctivities in volved in producing and distributing m ate ria ls and equipment, including the b a sic extraction and p r o c e ss in g o f raw m a te ria ls . The distin ction between the two a rea s m ay be useful in gaging the im m ed ia cy of the im pact o f a con stru ction p ro p o sa l. P rim a ry m an -h ou rs la rg e ly r e fle c t m a teria ls usage. Thus, the substantial em ploym ent in the stone, cla y , and glass products industry w ill be seen to r e fle c t in la rg e part the usage o f co n cre te and cla y sew er pipe. Secondary m an-hour requ irem en ts, by their definition, cou ld be analyzed only with r e fe r e n c e to the b a sic data on interindustry relation sh ips. 20 T able 4. M an-H our R equirem ents P e r $ 1,000 o f Sewer C onstruction C ontract, by P rod u cin g S ector and Stage of M anufacture, 1962-63 T otal m an-hour s P rim a ry m an -h ou rs Secondary m an -h ou rs A ll s e c t o r s ........... ................... 221.9 163.8 5 8 .2 On- site co n s tr u ctio n ......................... 84 .5 8 4 .5 A g r ic u ltu r e .......................................... M in in g ............................. ................... .. Other c o n s t r u c t io n ........................... M a n u fa c tu r in g ........................... Lum ber and lum ber products . . P aper and paper p r o d u c t s ......... P r in tin g ............................................ C h e m ic a ls ........................................ Stone, cla y, and glass products P rim a ry m e t a ls ............................. F a b rica ted m etal products . . . . M a c h in e ry ........................................ E le c tr ic a l p r o d u c t s ...................... T ra nsportation e q u ip m e n t......... Other m an u factu rin g.................... T ra n sp orta tion .................................... T r a d e ..................................................... S e rv ice s ............................................... Other i n d u s t r i e s ............................... 2 .2 4 .8 7. 2 7 2 .6 1.6 1.5 1. 1 1.6 26. 2 11.7 6.6 14. 1 4 .0 1.0 3. 2 10.6 23. 3 7. 3 9 .3 .2 1.1 5 .5 4 6 .8 .7 S ector Note: totals. — .2 2 2 .8 5. 7 3. 9 10.5 2.1 .2 .7 4.7 16.5 1.6 2 .8 2. 0 3 .7 1.7 2 5 .8 1.0 1.5 1.1 1 .4 3 .4 6. 0 2.6 3.6 1 .9 .7 2 .5 5.8 6. 8 5 .8 6 .6 B ecause o f rounding, sum o f individual item s m ay not equal 21 T otal o ff-s it e m an-hour requirem ents p e r $ 1,000 fo r con stru ction of the two prin cip al types o f sew er w o r k s — lin es and p la n ts--sh o w little differen ce: M an-hours p er $ 1,000 o f con tra ct fo r sew er w orks constru ction O ff- site Type o f fa cility A ll indus trie s O n- s it e : co n s tr u c tion T otal Con s tr u c tion Manu fa c turing T ra n s p o rta t io n , tra d e, and s e r v ic e s Other T otal hours: A ll sew er f a c i lit ie s .. . . . L ines . . . . . . . . . Plants . . . . . . . . 222 223 221 85 86 83 137 137 138 7 7 7 73 74 72 41 40 43 16 16 16 P rim a ry hours: A ll sew er fa c ilit ie s ......... L in e s . . . . . . . . . P la n t s ................ 164 168 159 85 86 83 79 82 76 5 5 5 47 51 42 23 22 25 4 4 4 Secon dary hours: A ll sew er f a cilitie s ......... L in e s .................. P la n t s ................ 58 55 62 - - 58 55 62 2 2 2 26 23 30 18 18 18 12 12 12 - - In the p rim a ry o ff-s it e ca tegory , lin es requ ire m o re m an -h ou rs than are req u ired by plants, because of the use o f m a te ria ls, such as pipe, o f a rela tiv ely low o rd e r o f fabrication , requiring m o re hours in the final stage. Plants use a greater value o f item s, such as p r o c e s s and con trol equipment, requiring m o re p ro ce ss in g p r io r to the final m anufacturing stage. 22 C ost of M aterials U sed The co s t of m a teria ls used in con stru ction o f the sew er w orks under study amounted to 56. 5 percen t of the con tract amount. F o r the lines it was 55. 7 percen t and for plants, 5 7 .4 . Included in these fig u re s are the value of the m a teria ls in corp ora ted into the various stru ctu res; the value o f p r o c e s s ing equipment and other types of in stalled equipment; the value o f supplies consum ed; and co sts o f con stru ction equipment rental o r estim ates of d e p re ciation allow an ces. T hey do not include co sts o f pu rchases o f overhead goods and s e r v ic e s . The prop ortion o f m aterials c o st to con tra ct amount va ried w id ely depending on p ecu lia rities of individual jo b s o r their relative p rofitab ility. Thus, high p roportion s often w ere a ssocia ted with unprofitable jo b s , or with jo b s which by their nature req u ired little o n -s ite constru ction, as fo r exam ple, the installation of a sm all treatm ent plaint using packaged equipm ent. T h re e -q u a rte rs of the con tra cts, how ever, showed m a te ria ls p roportion s within approxim ately 15 percentage points o f the average: L ines P ercen t m a te ria ls co st o f con tra ct amount T o t a l.................. Under 40 ................ 40 and under 50 . . 50 and under 60 . . 60 and under 70 . . 70 and under 80 . . 80 and o v e r ........... Plants Number of p ro je cts studied P ercen t o f con tra ct amount Number of p r o je c ts studied P e rce n t o f con tract amount 86 10 25 28 13 7 3 100. 0 5 .7 2 1 .4 36.5 23 .8 10.8 1 .8 52 2 7 24 10 8 100.0 1 1.0 11.0 55. 1 29. 6 2 .4 .9 T able 5 p resen ts the c o sts to the co n tra cto rs o f m a jo r m a teria ls and groups of m a teria ls used in each $ 1,000 o f sew er fa cilitie s con stru ction . M inor item s are included in group totals but a re not liste d separately. Data are shown fo r all p r o je c ts by region , and fo r lin es and plants separately. The table shows quite different patterns of m a teria ls usage fo r lin es and plants. F or lin es, n ea rly on e-h a lf o f total m a te ria ls co s t is accounted fo r by con crete and cla y pipe and an additional on e -fifth by the estim ate fo r con stru ction equipment usage. On the other hand, plant con stru ction uses a wide variety of m a teria ls, m any o f a high degree of fa brication , as might be expected from the va ried structures involved. In this r e sp e ct, the two m a teria ls patterns p a ra llel the two con stru ction occupational patterns p r e v iou sly d iscu ssed . 23 Some apparent anom alies in the table are explained by the design and techniques o f sew er fa cilitie s con stru ction . F o r exam ple, the greater relative use o f b r ic k and "oth er p reca st co n cre te p rod u cts" in lin es r e fle c ts the produ ction o f sew er m anh oles. The high requirem ents o f sand and gravel relative to cem ent, in r e v e r s e o f the usual pattern, suggest its use as a pipe bedding m a teria l in lin es, and as a filte r m edium in plants. Each o f the broad c a t e g o r ie s --lin e s and p la n ts --in clu d e s elem ents o f the other. This explains expenditures fo r pumps and m o to rs on line co n stru c tion. W here slop es are such that sewage cannot flow p ro p e rly by gravity alone, lift stations are requ ired . F inally, in view o f the great d iffe re n ce s between the line and plant m aterial patterns, the region al variations shown are as m uch a r e fle c tio n o f d ifferen ce s in product m ix as in lo c a l u sage. The breakdowns are thus applicable only to situations w here the m ix is assum ed to be s im ila r. 24 T able 5. C ost of M a teria ls p er $ 1,000 o f Sew er W orks C onstruction C ontract, by Type o f M a teria ls, R egion, and T ype o f P r o je c t, 1962-63 Item United States N orth east A ll p r o je c ts North South Central W est United States: lin es United States: plants T otal, all m a teria ls •.. ............. $ 5 6 4 .7 0 $ 5 3 0 .4 0 $ 5 3 3 .0 0 $ 5 7 0 .5 0 $ 6 2 1 .3 0 $ 5 5 7 .2 0 $ 5 7 3 .9 0 Stone, cla y , and glass produ cts •. $ 2 3 4 .6 0 Cem ent, co n cre te , and gypsum products 130.20 88.00 C on crete p i p e .............................. 29.80 R eady m ix ed co n cre te .............. 2.50 C oncrete b lock . . ................ ... .. Other p re ca st con cre te 7 .8 0 p r o d u c t s ......... ♦ . . . ................. .. 1.60 C e m e n t......................... . ............... $ 1 5 6 .1 0 $ 2 2 7 .9 0 $ 2 1 4 .7 0 $ 3 5 5 .4 0 $337. 30 $ 1 0 9 .3 0 7 9.80 33. 20 30.80 3.20 131.20 75. 20 38.30 2. 10 103.80 65.60 29.70 2. 10 231.50 201.40 18.60 3.30 179.90 147.40 16. 30 2.40 69.60 15.70 46.30 2.70 10.90 1.40 13.40 1.70 3.90 2.00 7 .00 1.00 11.50 2.00 3. 30 1.20 C lay p r o d u c ts ................................... C lay sew er pipe ......................... B r ic k ......................................... 77.40 67.8 0 8. 20 5 5.50 50 .7 0 2.70 67.00 57.30 8 .8 0 95. 20 80.40 13.00 6 9.90 67.80 1.70 124.30 113.40 10.80 20. 20 12. 20 5 .00 Other stone, clay, and glass p r o d u c t s ........................................... Sand and g r a v e l........................... A sb estos cem ent p i p e .............. M iscellan eou s a g g r e g a te ......... F ill d irt........................................... 27.00 17.70 6 .00 1.80 .60 20.80 10. 20 6 .10 3.30 . 30 29.70 24. 20 -3.00 .90 15.70 10.80 2.50 1. 10 .60 54.00 31.60 21.00 .80 .30 33. 10 22.80 7. 20 2.90 . 20 19.50 11.50 4 .5 0 . 50 1.00 M etal produ cts (excep t plumbing and heating).................................... P rim a ry m etal p r o d u c t s ........... Cast iron p ip e ......................... Steel pipe ................ ................... Steel sheet p ilin g ....................... Cast iron m anholes, e tc. . . . Aluminum sheet m e t a l ........... C opper sheet and p i p e ........... 105.70 56.00 34. 10 8 .0 0 5 .6 0 5 .5 0 1.70 .7 0 112.90 64.60 33.20 11.40 7 .4 0 5 .3 0 5 .40 1.20 90. 30 32.60 17.90 6. 20 .4 0 3 .6 0 3. 20 .8 0 133.00 77. 60 53.80 7 .7 0 8 .50 6 .5 0 (M .4 0 58. 20 30. 10 11.70 7 .7 0 3 .80 5 .60 . 10 .80 62. 30 47.80 28.50 9 .0 0 1. 30 8 .8 0 (M n 158.60 66. 20 4 1 .0 0 6 .7 0 10.70 1.40 3.60 1.60 F a b rica ted m etal p r o d u c ts .. . . . R ein forcin g rod s and b a rs; j o i s t s ..............••••••............. Structural steel .............. ••••• V alves and f i t t i n g s .................. Steel plate p r o d u c t s ......... .. F abricated sheet m etal produ cts ................................ . C orrugated m etal p i p e ............ Fencing . . . . . . . . . . . . . . . . . . . M etal d oors and fra m e s . . . . . M etal windows and fra m e s . . P refa b rica ted buildings . . . . . 4 9 .7 0 4 8 .3 0 5 7.70 55.40 28. 10 14. 50 92.40 15.30 8 .8 0 8 .30 4. 20 13.70 8 .4 0 9 .3 0 3 .40 20.80 9 .8 0 10.90 6 .7 0 15.30 8 .9 0 9. 10 4 .6 0 1 0 .Q0 7 .8 0 2.50 1.10 4 .7 0 .7 0 2. 30 1.70 28. 20 18.70 15.70 7. 30 3 .40 3 .3 0 1.80 1.40 1.10 .6 0 .6 0 6 .2 0 2.30 1.20 .9 0 — 1.40 .3 0 2 .60 1.60 1.60 .4 0 6 .4 0 4 .9 0 1.70 1.30 .7 0 1.00 1.70 .80 .6 0 1.50 1.60 .20 .6 0 2.90 .5 0 .3 0 .5 0 — 6 .7 0 3 .70 3 .40 2. 80 1.80 1.20 Sewage plant e q u ip m e n t.................. Pum ps and m o t o r s ......... ............. M ech anical c o l l e c t o r s ................ D ig esters, c l a r i f i e r s ......... .. D iffu sers and distribution equipment • • • . . . ................ L a b ora tory equipm ent and instrum ents E le c tr ic a l generating units . . . . C h lorin ators . . . . . . . . . . . . . . . . . E l e v a t o r s ................ .. U n sp ecified equipment ................ 69.90 27. 20 15.40 10.00 89.9 0 24.00 32.00 16.10 76.50 23.40 31.70 8 .5 0 71. 20 39.70 5 .5 0 4 .0 0 4 1 .4 0 7 .3 0 2.20 19.70 17.40 15.80 ... . 10 134.00 41. 20 34. 10 22. 10 5. 10 11.70 4 .7 0 4 .0 0 2.50 2.10 1.40 1.10 .9 0 6 .7 0 1.50 2.10 1.40 .3 0 1.00 2. 20 1.20 1.50 2.90 1. 10 .9 0 2.10 11.00 .70 1.90 .70 See footnote at end o f table - - 3 .30 6 .3 0 11.40 .6 0 . 20 .. . . 70 3.90 3.00 2.40 2. 10 14.00 25 T able 5. C ost o f M a teria ls per $ 1, 000 o f Sewer W orks C onstruction C ontract, by Type o f M a teria ls, R egion, and T ype o f P r o je c t, 1962-63—Continued Item United States N orth east E le c tr ic a l p r o d u c ts ........................... Sw itchboards and panelboards •. W ire and cable ................................ E le c tr ic a l m e te rs and instrum ents ••••.•••................ .. T r a n s fo r m e r s .................................. Conduit ................ ............... .. C u rren t-ca rry in g d e v i c e s ......... Lighting fix tu res ........................... $ 23. 30 12.80 2.30 $ 25.60 17.40 1.70 2.00 1.90 1.60 1. 20 1.00 P etroleu m p r o d u c t s ......................... F uel and lu bricatin g o i l s ............ A sphalt p a v in g ........................... .... A ll p r o je c ts North C entral United States: lin es United States: plants South W est $ 20. 30 8 .50 2. 70 $ 26.60 14.00 2.30 $ 1 7 .9 0 11.60 2.10 $ 3 .30 1.40 .8 0 $ 4 7 .7 0 2 6.80 4 .1 0 2.50 .3 0 1.50 .7 0 1.10 2. 80 .9 0 2. 10 1. 20 1.50 1.70 4 .0 0 1.60 1.60 .8 0 1.50 . 10 1.30 . 30 .8 0 . 20 C 1) .4 0 . 20 . 20 4. 20 4 .3 0 3. 20 2.40 2. 10 14.00 8 .7 0 4 .8 0 14.60 8 .50 5 .8 0 13.60 10.40 2.70 12.80 9. 10 3 .00 16.60 5 .70 10.50 16.80 9. 20 7 .40 10.60 8 .0 0 1.60 Lum ber and lum ber products . . . . D im ension lu m b e r ........... .. 6 .7 0 5 .40 7 .30 7. 10 5.50 3.70 7 .9 0 6. 10 5 .00 4 .5 0 4 .4 0 4 .2 0 9 .4 0 6 .9 0 Plum bing and heating m a teria ls and eq u ip m e n t.................................. Plum bing m a teria ls .................... Plum bing f i x t u r e s .................... 6. 20 1. 10 .50 8 .6 0 2.20 .70 8 .90 1. 10 .4 0 4. 10 .8 0 .6 0 5 .5 0 . 70 . 10 .4 0 . 20 — 13.40 2. 10 1. 10 Heating m a t e r i a l s ......................... B low ers and fans .................. .... B o ile rs and ra d ia tors, w arm air fu rn aces, unit h ea ters, and v e n t ila t o r s ......................... A ir-con d ition in g equipment . . 5. 20 2.40 6 .50 4 .6 0 7.80 4. 80 3.40 .9 0 4 .7 0 1.00 . 20 . 20 11.20 5. 20 1. 70 .60 1.60 1.50 1.40 1.20 .80 3 .30 C hem ical products ........................... Dynamite and caps ......................... Paint ................ ................. 3 .6 0 1.80 1. 10 4 .6 0 2.70 1.70 2.90 1.40 1. 20 1.50 . 20 .7 0 A ll other m a t e r ia l............................. N u rsery products ........................... 2.10 1.00 2.60 1.60 2.10 1.40 C onstruction equipment (rental ch arg es and d ep reciation a llo w a n c e s )......................................... 9 8.60 108.10 85.00 - - (>) 3.80 1.40 8 .20 5. 20 1.50 2.00 1.30 . 10 5 .6 0 2.50 2.40 2 .1 0 .9 0 1.50 .6 0 .90 3.50 1.80 9 6.70 111.70 1 L e ss than $ 0 .0 5 . Note: G roup totals include products not shown sep arately. — .4 0 112.50 81 .8 0 26 P rev iou s Studies T h ree previou s studies of la bor and m a teria l requirem ents fo r sew er con stru ction have been m ade in the BLS co v e rin g data relatin g roughly to 1934, 1940, and 1949.4 D ifferen ce s in scop e, sam pling, cla s s ifica tio n , and data c o lle c tio n in these e a r lie r studies and the curren t one lim it the usefu ln ess o f com p a rison s. H ow ever, som e con clu sion s appear reasonable: O n -site con stru ction w ork er w ages as a percentage o f the total con tract amount w ere as low in 1962-63 as they had been at any tim e over the previou s 30 y e a rs; the percentage o f com bined overhead and p ro fit, on the other hand, was as high or higher them it had been in the sam e 30-y e a r p e rio d . P e rce n t o f con stru ction con tra ct amount 1962-63 T o t a l ............................................... W ages to o n -site w o r k e r s ........... M aterials and supplies ................ Other costs and p rofits ................ 1949 1940 1934 100 32 44 24 100 30 50 20 100 26 51 23 Other co sts include con stru ction equipment dep reciation , w hich was not shown separately in the e a r lie r studies, and em ploym ent c o s ts other than w ages paid to o n -s ite w o r k e r s . Both o f these c la s s e s o f co sts are b e lie v e d to have in cre a se d as a percentage o f total con tra ct c o s t ov er the y e a r s . 4 "R ela tive C ost o f M aterial and L abor in C onstruction o f W ater a Sew erage S y s te m s ," M onthly L abor R eview , January 1935 (based on data c o lle c te d at around 1934), pp. 146-146; " E xpenditures fo r L abor and M aterial and M an-H ours o f L abor C reated per $ 1 m illio n o f C ontracts A w arded fo r Sew ers and Sew erage S ystem s, " BLS m im eograph ed re le a s e , N ovem ber 1944 (based on data c o lle c te d at around 1940); "E xpenditures per M illion D olla rs fo r C onstruction o f New W ater Supply and Sewage D isp osal System s, " BLS m im eographed r e le a s e , M ay 1951 (based on data fo r 1948-50). 27 The o v e r a ll percentage o f m a teria ls co st in total c o st appears to have d e cre a se d only slightly over the y e a rs, but there have been significant shifts in the rela tiv e im portance o f som e m a te ria ls . The use o f lum ber products has d ecrea sed , probably re fle ctin g the greater use o f steel shoring and p refa b rica ted fo r m s . The total amount o f "co n c r e te p rod u cts"-h a s in crea sed , and the amount o f cem ent and aggregates has d e cre a se d , as re a d y -m ix e d con crete has rep la ced site -m ix e d . C on crete products also appear to have gained at the expense of b rick , w here p re ca st co n cre te m an h oles and m anhole section s have rep la ce d b rick m anh oles. F o r the e a rlie st two studies and the latest, o v e ra ll m an -h ou rs data are available, suggesting the p o ssib ility o f m easurin g changes in output per m an-hour ov er the 3 0 -y ea r p eriod . The available data, h ow ever, do not relate produ ction m an -h ou rs to units o f physical output, such as linear feet o f pipe laid, but only to d olla rs of con tra ct amount. T hese d olla rs m ay rep resen t different ph ysical quantities at different tim es owing to co n s tr u c tion p r ic e changes. T o m ea su re the change in m an-hour requirem ents fo r equivalent amounts of con stru ction , it is n e c e s s a r y to adjust the d olla rs for p r ic e changes so that they rep resen t approxim ately equal ph ysical quantities. Making such an adjustm ent in the case o f sew er con stru ction resu lts in an indicated in cre a se o f 40 to 50 p ercen t in output per m an-hour over the 30year p e rio d . A part o f this in cre a s e resu lted fro m the tra n sfer o f certain o p e ra tions fro m o n -s ite to o ff-s it e loca tion s, as fo r exam ple, the prefa b rica tion o f fo r m s fo r co n cre te w ork, the p reca stin g of som e co n cre te produ cts, the prem ixin g of c o n cre te , and even the m anufacture of jointing elem ents on som e piping. H ow ever, a part of the in cre a se is due to im p roved m ethods, p a rticu la rly in excavation. 28 S cope and M ethod o f Survey Sample T h is study is based on data co v e rin g 138 prim e con tra cts fo r the con stru ction of sew er fa c ilitie s . Of th ese, 85 w e re con stru cted under the W ater P ollution C ontrol P rog ra m o f the P ublic Health S erv ice, and 53 under that part of the A c ce le r a te d P ublic W orks P ro g ra m w hich was adm inistered by the Com m unity F a c ilitie s A dm inistration. The w ork under the fo rm e r p rogram was done ch iefly in 1962 and 1963; w ork under the latter program was accom p lish ed ch iefly in 1963. The sam ples each rep resen ted about 1 in 8 o f the total num ber o f p r o je c ts undertaken by these agen cies during the re sp e ctiv e p e r io d s . Sample p r o je c ts w ere lo ca te d in 44 States and the D is tr ic t o f Colum bia. T o obtain a represen tative sam ple, p r o je c ts w ere se le cte d by type o f p r o je c t, broad geographical region , amount o f con tra ct, and whether with in o r outside a m etropolitan a rea . The distribution o f the sam ple p ro je cts by these c a te g o rie s is shown in table A - l . In tabulating the data, how ever, w eighting was applied to adjust fo r nonrespondents, and fo r som e d ifferen ces in p r o je c t c h a r a c te ris tic s d is c lo s e d in the c o u rs e o f the su rvey. U nless otherw ise stated, all m ea su res presen ted in the re p o rt a re based on weighted data. M an-hour E stim ates E stim ates o f total m an-hour requ irem en ts fo r sew er con stru ction a re derived by com bining estim a tes o f o n -s ite and o ff-s it e m a n -h ou rs. O n -site m a n -h o u r s . With m in or exception s, con stru ction under both the F e d e ra l W ater P ollu tion C ontrol P rog ra m and the A c c e le r a te d P ublic W orks P ro g ra m is subject to p revailin g wage law s. T o ch eck com p lia n ce with these law s, regulations req u ire that each con tra ctor on such con stru ction file a cop y o f h is w eek ly p r o je c t p a yroll with the spon sorin g agency. T h ese pay r o lls are thus a p rim a ry sou rce o f data on con stru ction m an -h ou rs w orked and w ages paid on a p r o je c t. In the cu rren t study, the p a yroll file s fo r the sam ple p r o je c ts w ere m ade available fo r data tra n scrip tion through the coop eration o f the P ublic Health S e r v ic e 's D ivision of W ater Supply and P ollu tion C ontrol and the Com m unity F a c ilitie s A d m in istra tion 's Public F a c il itie s D ivision . Although these p a y rolls w ere the b a sic so u rce o f o n -s ite la bor data, som e c la s s e s o f o n -site w ork ers are exem pt fro m the legal rep ortin g re q u ire m en ts. T hese exem ptions include su p ervisory, tech n ical, and c le r ic a l p e r sonnel, and se lf-e m p lo y e d su b con tractors (w orking p r o p r ie to r s ). M o re o v e r, the p ro ce ss in g o f the p a y rolls ra is e d frequent questions regardin g data co m pleten ess and m eaning. T hese m issin g data w ere obtained and questions con cern in g data m eaning r e so lv e d by telephone o r co rre sp o n d e n ce , o r , m ost com m only, through v is its by BLS fie ld rep resen ta tiv es, in the c o u rs e o f the m a te ria ls data c o lle c tio n . T a b le A - l . . N um ber o f S am ple C o n tr a c ts in S e le c te d C a te g o r ie s Under $ 5 0 ,0 0 0 $ 5 0 ,0 0 0 and under $ 100, 000 T o ta l M e t r o N on m et M e tr o N o n m e t p olita n rop olita n politan ro p o lita n area a re a a re a a re a $ 1 0 0 ,0 0 0 and u nder $ 3 0 0 ,0 0 0 $ 3 0 0 ,0 0 0 and under $ 500, 000 M e tr o N o n m e t politan r o p o lita n area area M e t r o N on m et p olita n ro p o lita n a rea a re a $ 5 0 0 ,0 0 0 and under $ 1 ,0 0 0 ,0 0 0 $ 1 ,0 0 0 ,0 0 0 and o v e r M e t r o N on m et politan rop olita n a re a a re a M e t r o N on m et p olitan rop olitan a re a area T o t a l ............... 138 11 12 10 15 18 27 8 15 7 4 9 2 L in e s , to ta l. . . . N o rth e a st •, . N orth C en tra l South ............... W e st ............... P la n ts, t o t a l . . . N o rth e a st . . . N orth C en tra l S o u t h ............... W e st ............... 86 19 23 28 16 52 9 16 9 4 4 1 0 2 0 1 1 0 4 1 1 1 1 8 0 4 4 0 8 0 4 2 2 2 1 0 1 0 10 2 1 5 2 5 1 2 0 2 9 5 2 1 1 9 3 2 0 4 19 1 5 7 2 1 3 1 1 0 0 1 0 8 3 3 2 0 7 1 2 3 5 0 1 1 3 2 1 0 0 1 2 1 0 0 1 2 1 0 1 0 5 0 1 2 2 4 1 2 1 0 0 0 0 0 0 2 0 1 0 1 17 10 ro 3 8 0 2 5 1 1 30 O ff-s ite m a n -h o u rs . O ff-s ite m an-hour requ irem en ts in con stru ction r e p resen t ch iefly the hours requ ired to produce and distribute the m a te ria ls, supplies, and equipment used. E stim ation o f these h ou rs th e re fo re began with a listin g o f the value o f a ll such ite m s. F o r the p resen t study, this listin g was obtained in one of two w ays. F o r jo b s under $500, 000, a m a il questionnaire in itially was used. 5 F or la rg e r jo b s , and fo r nonrespondents on the sm a ller jo b s , data w ere obtained in v isits by BLS fie ld rep resen ta tiv es. F o r a re la tiv e ly sm all num ber o f su bcon tractors who w ere out of business o r otherw ise in a c ce s s ib le , uncooperative, o r w hose con tra cts w ere e x c e e d ingly sm all, estim ates o f both la bor and m a teria ls w ere prep a red on the ba sis o f rep orts fo r sim ila r jo b s . In all, the study o f the 138 sam ple p r o je c ts requ ired contact o f (o r estim ates for) 645 prim e and su b con tra ctors. The m a teria ls listin gs thus obtained w ere c la s s ifie d into ca te g o rie s (consistent with the 4 -d ig it Standard Industrial C lassification ) as found in the Census o f M anufactures product groups. F o r each o f these groups, the average amounts req u ired for $ 1 ,0 0 0 o f sew er fa cilitie s con stru ction w ere calculated. Each o f these averages was redu ced by a ratio represen tin g the differen ce between m an u factu rer's and c o n tr a c to r 's valuation. The amounts thus redu ced w ere consistent with Census data published fo r these variou s com ponents. P rim a ry m an -h ou rs fo r m anufacturing sew erage m a teria ls (i. e . , the hours req u ired in the final m anufacturing stage) w ere developed by m ultiplying these average amounts by a ratio o f m anufacturing m an -h ou rs to $ 1, 000 o f produ ction . T hese ratios w ere com puted fro m the output and em ploym ent data in the 1962 Survey of M anufactures. P rim a ry m an -h ou rs for trade and transportation w ere derived in a sim ila r m anner. H ere, h ow ever, em ploym ent ra tios w ere applied to the differen ce between p r o d u ce r 's and p u rch a s e r's valuation, which was taken as the total o f all distribution c o s ts between the sites o f final m anufacture and con stru ction. T o com pute secon da ry m an -h ou rs to produ ce the m a teria ls (i. e . , hours req u ired in all stages o f production other than final m anufacture and transportation), the 1958 interindustry study by the O ffice o f B usiness E con om ics o f the U .S . Departm ent o f C om m erce was used. T his study 5 The questionnaire requested detailed inform ation on type, quant and cost o f m a teria ls and supplies; equipment d ep recia tion and rental c o s ts ; and su bcon tractors (nam es, a d d resse s, nature o f w ork and subcontract am ounts), the su b con tractors, in turn, a lso being sent a cop y of the que stionnair e . 31 indicates the amount o f secon dary product or s e r v ic e re q u ire d o f each o f its 78 industry s e c to r s to produ ce the p rim a ry product. Summing these amounts and applying the appropriate em ploym ent ratios produ ced the num ber o f s e c ondary m an -h ou rs req u ired in each o f the s e c to r s . Two other m in or com ponents w ere req u ired to com p lete the co m p i lation o f total o ff-s it e hours as defined fo r this s e r ie s o f stu dies. One o f these is the hours req u ired to produce the c o n tr a c to r s ’ pu rchases o f o v e r head m a teria ls and s e r v ic e s . The quantities o f these item s w ere estim ated and included in the m an-hour con v ersion s ju st d e scrib e d . The other is the h ou rs w orked by the o ff-s it e em ployees o f the con stru ction industry. The estim ate fo r these h ou rs is based on the d ifferen ce between the p roportion o f all nonconstruction w o rk e rs in the con tract con stru ction industry as re p o rted in the BLS em ploym ent trend s e r ie s , and the prop ortion o f o n -site n on con struction m an -h ou rs as developed in this study. * U. S. GOVERNMENT PRINTING OFFICE : 1966 O - 219-825