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1 7KH&RPSDULVRQEHWZHHQ3ODVWLFDQG 7UDGLWLRQDO,QVSHFWLRQ&KDPEHUVXQGHU /DERU3URGXFWLYLW\(YDOXDWLRQ 265H]HQGH1HWR8(/GH6RX]D&$6DXWFK~N (1) (2) (3) (1), (3) Escola Politécnica, Universidade de São Paulo, Brazil (2) Civil Construction Engineering Department, Escola Politécnica, Universidade de São Paulo, Brazil $EVWUDFW This paper discusses labor productivity for the execution of inspection chambers for sewer systems. There were collected 211 data points in a daily basis during the execution of inspections, manufactured with plastic materials and also with traditional materials (mortar, brick, and rings of concrete). It was developed a methodology for collecting data in site and for processing these data. The results represent a solid base of data (collected in a sewer system implemented in Brazil, in 1998) that can be used to compare productivity between installing traditional and plastic inspection chambers..h\zrugv Inspection Chamber; Labor Productivity E1 1/9

2 ,QWURGXFWLRQ Sewer System is very important for population health and environmental preservation. So that it is necessary to reduce costs of implementation, maintenance and operation, allowing that more people can be linked to the sewer system. For this cost reduction, it will be necessary to develop new technologies and new concepts of design. Related to technology, the use of plastic for sewer system is an alternative that is being implemented in Brazilian Construction, using all the accessories and pipes in plastic. This research discusses the implementation of inspection chambers, comparing plastic technologies and traditional ones, in terms of productivity. This labor productivity was measured during the execution of a sewer system using these two different technologies. The plastic technology uses plastic pipes and all accessories are also made of plastic. For the traditional technology, inspection chamber is made of traditional construction material like bricks; rings of concrete and pipes are made of ceramic or concrete. Bricks Concrete rings cimento cement )LJXUH0DWHULDOVXVHGLQWKHFRQVWUXFWLRQRILQVSHFWLRQFKDPEHU The study uses a database gathered from construction sites. A partnership between CEDIPLAC (Centro de Desenvolvimento e Documentação da Indústria do Plástico para a Construção Civil) and CAESB (Cia. de Água e Esgotos de Brasília) that is a public sewer company, made the data collection possible. Two geographic areas were studied; the first one is called Recanto das Emas and the other one, Riacho Fundo II. Both of them are located in Brasília, Brazil. For this research, it was necessary to develop a methodology to quantify the labor productivity, which was composed of collecting site data and also processing them through tables that were specially developed for it. The result is presented using tables that show productivity data for each type of material and for various diameters, analyzing the advantages for the use of plastic inspection chambers. E1 2/9

3 ,QVSHFWLRQ&KDPEHUIRU6HZHU6\VWHP 'HILQLWLRQ Most Inspection Chambers or Manholes are circular in shape and must allow the system inspection and cleaning. Inspection Chamber should be placed at all changes in sewer grade, pipe size, or alignment; at all intersections; at the end of each line; and at distances no greater than 100 m for sewer pipes with a diameter equal or superior of 150mm. For diameter equal to100 mm, it should be adopted distances between 40 and 50 m. Figure 2 shows the sewer system parts as they were considered by this research. Inspection Chamber Sewer Line (pipe) Inspection Chamber 7UDGLWLRQDO,QVSHFWLRQ )LJXUH±6FKHPDWLFRILQVSHFWLRQDQGVHZHUSLSH 7\SHVRI,QVSHFWLRQ&KDPEHUV There are different types of inspection chambers, as showed in Figures 3 and 4. Figure 3 shows an inspection called in Brazil PV-Poço de Visita which has an irregular shape, because there s a difference between the upper section and the bottom one. In figure 3, there is also another inspection chamber called in Brazil TIL ( Tubo de Inspeção e Limpeza ), which has a uniform section, with no eccentric slab. PV and also TIL are traditional inspection chambers often used in sewer systems with traditional methodology. Terminal Cleanout (called in Brazil TL) is another inspection chamber, less used than the other ones (Figure 4). TL is just used in the beginning of sewage to allow the introduction of maintenance equipment. Inspection Chambers (CI) are used in the entrance of each house that is linked in the network.(as showed in Figure 3) PV Concrete cover TIL Cover CI Concrete Cover Concrete Rings Concrete Rings Eccentric Slab Concrete Rings for the Wall for the Wall Concrete Rings Brick Walls Concrete Slab Compacted Sand Brick Walls Concrete Slab Compacted Sand Pipe Concrete Base )LJXUH±6FKHPDWLFRI7UDGLWLRQDO,QVSHFWLRQ&KDPEHUV397,/DQG&, E1 3/9

4 TL Cast Iron Cover Concrete Block Ceramic Pipes Foundation (concrete) Ceramic Fitiings )LJXUH±6FKHPDWLFRI7HUPLQDO&OHDQRXW,QVWDOODWLRQ PVs are made at the site using construction materials like bricks, precast concrete rings, reinforced concrete slabs, ceramic pipes and fittings, concrete, cement, sand, and others by Alem Sobrinho and Tsutyja (1999). As presented in Figure 3, the following parts compose an inspection chamber: 1. Compacted sand for the base; 2. Foundation using reinforced concrete slab; 3. Bricks for the wall; 4. Precast concrete rings for the bottom part of the body ; 5. Eccentric slab; 6. Concrete rings in the 600mm diameter for the upper wall, forming the access; 7. Covered generally is made of Reinforced Concrete or Cast Iron, and this last one is used in places where you have traffic; When the PV or TIL is located in places with high water table, it is necessary to waterproof their external and internal surface. The TL is made using ceramic pipes and fittings, with concrete foundation and it is necessary to embrace the ceramic fittings with concrete to assure the stability. Traditional inspection chamber production demands more labor and also uses heavier equipment to transport components like precast concrete rings and prefabricated reinforced concrete slabs. Because of these facts, the productivity for installing traditional inspection chambers is worse than for plastic one (that implies just an assemblage). 3ODVWLF,QVSHFWLRQ&KDPEHU 7\SHVRI3ODVWLF,QVSHFWLRQ&KDPEHUV In Brazil, there are two types of inspection chambers; the first one is the Radial Inspection Chamber, which is used with pipes in a diameter between 100 and 300 mm. These inspection chambers are used as an alternative to the traditional inspection chambers (PV and TIL). E1 4/9

5 It generally has circular shape and is composed by the following parts: 1 Cover 2 Inspection Pipe 3 Body 4 - Base 2 1 Internal Chambers 3 4 )LJXUH'HWDLORIDQLQVSHFWLRQFKDPEHU It is designed to resist the efforts caused by traffic. Generally made of Polyethylene (PE), this kind of inspection chamber has inside chambers that are important to direct the sewage. For connecting pipes in the chambers, it is necessary to use gaskets. Its size and shape make possible the installation of it without using concrete for fixing it. When water table is high, it should be necessary to use concrete for the assurance of stability. Another advantage is that internal surface is very smooth, allowing the perfect flowing for sewage and also avoiding points of accumulation. Internal shape was designed to facilitate operations of cleaning and inspection. (Figure 5). In Figure 6, there is also an inspection chamber that is used to collect the sewage from the houses or buildings in substitution of traditional inspection made of concrete or brick. )LJXUH6HUYLFH&RQQHFWLRQIRUVDQLWDU\VHZHU,QVWDOODWLRQRI3ODVWLF,QVSHFWLRQ&KDPEHU Because of plastic inspection chamber is industrially manufactured, the installation is just an assemblage, involving generally two people that are capable to do all the steps for installing it. The steps are similar to the traditional techniques, i.e., once the trench is opened; it is just to lay the Inspection and then, cover it with soil. If sometimes the water table is high, it can be necessary to concrete the inspection in its base to assure the stability. E1 5/9

6 There is also a reduction of material loss and an improvement of labor productivity when compared with traditional technologies. The quality is guaranteed because it is the manufacturer s responsibility, reducing the interference of labor in that way. In figure 7 it is possible to see an installation of a plastic inspection chamber in a sewer system. )LJXUH,QVWDOODWLRQRI5DGLDO3ODVWLF,QVSHFWLRQ&KDPEHU /DERUSURGXFWLYLW\LQWKHLQVWDOODWLRQRILQVSHFWLRQFKDPEHUV Labor productivity study was done aiming to get information about the reality of sewer systems production, which are built with lots of interference. In terms of productivity in a Traditional Sewer System, the installation of an inspection chamber is a very critical part of the execution once it involves several construction activities, such as the base (foundation), the concrete slabs and also the laying of concrete rings. According to several authors, when comparing labor productivity data, the installation of plastic inspection chamber presents better productivity rates than the installation of traditional ones. 'HILQLWLRQDQG0HWKRGXVHGLQWKLVUHVHDUFK Productivity is the efficiency in transforming ODERU (effort) into a finished service ( results ). In the case of inspection chamber, effort is measured in terms of demanded work hours and the number of installed inspection chambers quantified the result. The work hours result from the multiplication of the number of workers involved in the service by the worked hours. The concepts that are described here are discussed by Souza (1996). For determining productivity in the installation of plastic inspection chambers, there were developed a methodology of collecting data and also processing it, considering just the inspection instead of all the system. Sewer system was considered in parts (as said before), and the productivity of all system was also measured, but it is not included in this paper. E1 6/9

7 A specific person that was hired just to do this job, using tables in the site and also taking notes about any extraordinary events had registered the data collected in a daily basis. After collecting data, they were reconciliated in order to assure the validity of these results. Data were then processed and the results were analyzed. Table 1 was used to help site collection; Table 2 was useful to calculate labor productivity rates. 7DEOH&ROOHFWLQJ'DWDIRULQVSHFWLRQ&KDPEHU,QVWDOODWLRQ Identification of Sewer Line Characteri stic Number of Inspection Type of Inspection Material Team Work Hours Work Hours (Wh) Total Wh Extraordinary Events 7DEOH±&ROOHFWLQJVHUYLFHVGDWDIRULQVSHFWLRQFKDPEHULQVWDOODWLRQ &RQVWUXFWRU Place Type Of System Period of Collected Data Type Of Inspection 7DEOH3URFHVVHG'DWD Material Diameter in mm Depth in m Work Hour Wh Quantity of Inspection(unit) Wh/unit &DVHDQG5HVXOWV 7DEOH±3URFHVVLQJFROOHFWHGGDWDLQVLWH The characteristics for the studied place are: plane topography; the soil has good mechanical resistance and the streets are not paved with asphalt. The amount of plastic inspection chamber researched was units. Part of this amount, 1068 units, were used for sewer systems with a diameter of 100 mm while174 units represented inspections for sewer systems with diameters varying between 150 mm and 300mm The researched amount of Traditional Inspection Chamber was 81 units. Part of this amount, 63 units, were used for sewer systems with a diameter of 100 mm while18 units represented inspections for sewer systems with diameters varying between 150 mm and 300mm. E1 7/9

8 5HVXOWVDQG&RPPHQWV The results represent the mean value of productivity for different diameters and types of inspections. The work hours included delay and rework. Table 3 presents a summary of plastic inspection productivity figures. It shows that there is almost no variability in comparing the rates for different diameters of plastic inspections. 7\SHRI,QVSHFWLRQ 'LDPHWHU PP 0HDQ9DOXH RI'HSWK +LQPP :RUNKRXUV :K 4XDQWLW\RI,& XQLW Radial IC * 100 0,70 to 1,75 223, ,21 Radial IC * 150 to 300 1,20 to 1,98 47, ,27 5DGLDO,& WR WR *IC=Inspection Chamber 7DEOH±3ODVWLF,QVSHFWLRQ&KDPEHU3URGXFWLYLW\ :KXQLW Table 4 presents the mean value of labor productivity for traditional inspection chambers. As showed in this table, there are great differences if comparing different diameters. For CI the mean value for productivity is 0,42 Wh/unit while for TIL the unit rate reached 8,72 Wh/unit. For PV mean value of productivity was 12,13 Wh/unit. 7\SHRI,QVSHFWLRQ 'LDPHWHU PP 0HDQ9DOXH RI'HSWK +LQPP :RUNKRXUV :K 4XDQWLW\RI,& XQLW :KXQLW CI 100 0,40 to 0,77 9, ,42 TIL 100 0,59 to 1,20 357, ,72 PV 150 to 400 1,37 to 1,90 218, ,13 7DEOH7UDGLWLRQDO,QVSHFWLRQ&KDPEHU3URGXFWLYLW\ Table 5 presents the improvement of productivity when comparing results from both types of inspections: Plastic and Traditional. In this table, it is possible to evaluate the advantage in using Plastic Inspection Chambers for diameters between 150 mm and 300 mm. The demanded effort to assemble one (1) Traditional Inspection Chambers (T) is the same as for assembling forty-five (45) Plastic Inspection Chambers (P). 3ODFHLQVWDOOHG,QVSHFWLRQ &KDPEHU Sewer House connection Public sewer system Public sewer system 'LDPHWHU PP 7HFKQRORJ\ PDWHULDO 3URGXFWLYLW\ :KXQLW 5HODWLRQEHWZHHQ TXDQWLW\RI,QVSHFWLRQV 7UDGLWLRQDO[3ODVWLF 100 Plastic 0,21 Traditional 0,42 1T=2 P 100 Plastic 0,21 1T=40 P Traditional 8, to 300 Plastic 0,27 1T=45 P 7DEOH,PSURYHPHQWRISURGXFWLYLW\XVLQJ3ODVWLF7HFKQRORJ\ *Where T=Traditional and P=Plastic E1 8/9

9 &RQFOXVLRQ With the results presented in table 5, it was possible to conclude that labor productivity for inspection chambers depends on the technology involved. Plastic Technology demands less labor, reducing costs. The figures showed in this paper can help managing a sewer system implementation. It was possible to see that the differences do exist when comparing materials, not diameters. Besides, Plastic Technology has a better quality because all of its components are industrially manufactured by Ilha and Teixeira (1997). Also, Traditional Technology depends on the combination of labor involved in the execution and also on the quality of different components. 5HIHUHQFHV 1. SOUSA, Ubiraci Espinelli Lemes. (1996) 0HWRGRORJLD SDUD R (VWXGR GD 3URGXWLYLGDGH GD 0mR GH 2EUD QR 6HUYLoR GH ){UPDV SDUD (VWUXWXUD GH &RQFUHWR $UPDGR: Tese de Doutorado apresentada na Escola Politécnica da USP. São Paulo. 2. ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR 9814 (1987) ([HFXomRGH5HGH&ROHWRUDGH(VJRWR6DQLWiULRRio de Janeiro. 3.. NBR (1988) &RQH[}HV GH 39& 5tJLGR FRP -XQWD (OiVWLFD SDUD &ROHWRU6DQLWiULR±7LSRVH'LPHQV}HV Rio de Janeiro. 4. EPUSP/CEDIPLAC (1997) 6LVWHPDVSOiVWLFRVHP39&SDUDUHGHFROHWRUDGH HVJRWRVDQLWiULR Manual de Execução, Vol.2 São Paulo. 5. TSUTIYA, Milton Tomoyuki; ALEM SOBRINHO, Pedro (1999) &ROHWD H 7UDQVSRUWHGH(VJRWR6DQLWiULR Departamento de Engenharia Hidráulica e Sanitária da Escola Politécnica da Universidade de São Paulo, 1 a. Ed., 548 p, São Paulo. 6. UNI-BELL PLASTIC PIPE ASSOCIATION (1979) +DQGERRNRI39&3LSH'HVLJQ DQG&RQVWUXFWLRQ. 306 p, Dalas, Texas. 7. TEIXEIRA, Eglé N.; ILHA, Marina S. O (1997) 5HGHV&ROHWRUDVHP39& Anais do II Encontro Tecnologia de Sistemas Plásticos na Construção Civil - São Paulo, Brasil, pp CONVÊNIO CAESB& CEDIPLAC (1999) 5HODWyULR 7pFQLFR GH,PSODQWDomR GDV 2EUDVHP%UDVtOLD E1 9/9