INTRODUCTION:
The productivity of labour in the construction industry is of critical importance since labour costs account for 30%– 60% of the total project cost. It is therefore evident that the profitability of any project depends on the productivity of its labour force to a very large extent. The construction industry has been experiencing chronic problems, such as poor management, poor working conditions, and insufficient quality that affect construction productivity and will affect a company’s performance and the overall economy of the country (El-Gohary and Aziz, 2014). Labour productivity depends on factors such as availability of work front, availability of material, availability of equipment, waiting for instructions etc. Additionally, labour productivity shall also depend on time spent in transit to collect material, to use a sanitary facility etc. Productivity is a function of the proportion of direct work and the proportion of support work. Direct work and support work shall be the minimum time required to complete an activity if working conditions are perfect, design and specifications at an optimum, and if there is no time loss (Drewin, 1982), which in turn translates to increased productivity. Unhygienic and inadequate sanitary conditions may raise many issues on construction sites for uneducated labour, thereby affecting their health and safety which in turn will affect the productivity of the labour. In view of the above, a study has been undertaken on the benefits of providing portable sanitary facilities at a construction industry.
LITERATURE REVIEW:
The construction industry is highly disorganized and peripatetic in nature. The uniqueness and non repetitive operations of construction projects make it difficult to develop a standard productivity definition and measure (Sweis, 2000 and Oglesby et al., 1989). Thomas and Raynar (1997) studied the effect of scheduled overtime to improve the time availability for project timely completion and concluded that scheduled overtime is a source of disturbance, as it may cause loss of labour efficiency. Thus time availability can be improved by reducing the travelling time of labours within site premises. As per OHSA standards, sanitation facilities should be provided separately for labours in construction site and it also helps to improve hygienic conditions. Hanna et al. (2005) proved that hygienic conditions was one of the reasons for absenteeism and quantified the impact of frequent absenteeism on labour productivity. Chuck et al. (2009) stated that Portable toilets are a simple, economical and usable in remote or difficult areas. From this literature review, the following research issues are required to be addressed,
(a) Labour productivity:
In construction projects, productivity can be measured in terms of work done in a given time; depends on availability of work front, availability of material, availability of equipment, waiting for instructions etc. Additionally, it also depends on time spent in transit to collect material, to use a sanitary facility etc.
(b) Travelling time:
One of the major concerns is the effectiveness of the jobsite layout of a project where in a lot of time is spent in travelling from one place to another (non-productive time) on the pretext of using toilet facility, obtaining material, lunch and other purposes. However, during the work if a worker travels more distance just to use the sanitation facility, it not only hampers the productivity of the worker itself but also the project in terms of time and cost. It is further inferred from the above mentioned issues that provision of sanitation facility at a construction site should be mandatory in order to maintain good hygiene for labour, which needs to be addressed.
METHODOLOGY:
The study methodology is as explained in Figure 1.
Figure 1: Study Methodology
Case study
i. Selection of construction sites:
Various phases of construction sites such as sub structure phase, super structure phase and finishing phase were selected for the study. Five different sites were selected and analysis has have been done. Out of the selected five, one case has been discussed below.
Case: Residential project of 7,48,254 square foot area, which was divided into three block. Each block consists of two basement floors, ground floor and 28 upper floors and total duration was 36 months. At the end of 8 months block A was completed up to 4th upper floor level, block B up to 1st basement level and block C up to 2nd upper slab level. Location of blocks, labour camps, paths used by labour for both existing and proposed sanitation facility was shown in figure 1.
Figure 1: Existing layout of site
ii. Data collection:
Data were collected at the construction site taking the following variables into account using time study: Distance travelled was measured by pace value and number of step required in reaching nearby sanitation facility. Pace value of person was measured in respective site ground conditions to increase reliability of data. Time taken by a labour to reach nearby sanitation facility was measured using stop watch. Few important criteria were considered for location of the facility like labour distribution, ease of access and space requirement.
iii. Analysis of data
Comparative analysis was adopted to quantify the benefits by the provision of sanitation facility near to work place in terms of increase in time availability and respective cost implications. Few terminologies used are explained below
· Cycle Time (CT) :
It is the time taken by a labour to travel back and forth between work place to nearby sanitation facility within site premises in minutes. In this study time taken for use of sanitation was not considered. Cycle time was measured in actual site environment using the formula below,
· Distance travelled (DT) :
It is the total distance travelled back and forth between work place and nearby sanitation facility by a labour is termed as distance travelled. Distance travelled was calculated by multiplying the pace value of each person and number of step required to reach nearby sanitation facility. Pace values for each person were calculated on the site ground condition to increases the accuracy of the data collection. Mathematically,
· Loss in Mandays (LM) :
It is the total time spent by all labours in construction site for use of nearby sanitation facility in a given manday. In this study, losses in mandays were calculated by assuming all the labours in construction site using the sanitation facility for three times in a day and 8 hours per manday. Mathematically,
· Percentage of loss in mandays (% LM) :
It is the ratio of loss in mandays to total mandays available. Total mandays available will be product of number of labours and eight hours. It will quantify the percentage of mandays lost due to use of nearby sanitation facility. Mathematically,
· Cost of productive time (CPT) :
It is the cost incurred by a labour for use of nearby sanitation facility during productive hours in a given manday. In this study, as mentioned earlier it was assumed that all labours were using a sanitation facility for three time in a manday, so weighted average of daily labour wages of all trades in construction site was used for calculation. Mathematically,
CPT 
· Total loss (TL) :
It is the products of labour wage spent for use of nearby sanitation facility and number of labours in the construction site. It was calculated in terms of Rupees per manday. Mathematically,
TL 
· Percentage of labour cost (PLC) :
It is the ratio of the total loss to total labour wages. It will quantify the percentage of labour wages were spent on use of nearby sanitation facility. Mathematically,
· Cost of facility (CF) :
It is the total cost spent on the provision of portable sanitation facility and cost of cleaning on daily basis. It will depend on the suppliers, type of facility, and capacity of the facility (i.e., number of users per unit of facility per manday). Cost of facility was calculated based on the cost of one sanitation unit and number of sanitation unit required for a given construction site. Mathematically,
Where,
K = type of facility used in construction site.
· Cost implications (CI) :
It is the difference between the total loss of existing facility per manday and sum of total loss of proposed and cost of facility per manday. Positive value of cost implication refers to saving in mandays and cost after providing the portable sanitation facility. It was calculated in terms of Rupees per manday. Mathematically,
CI
RESULTS AND DISCUSSIONS:
In the existing construction project, no sanitation facilities were provided nearby the work places and all labours have to use the sanitation facilities which were provided in labour camps which make the labour travel longer distance and take proportionally longer time. Based on the observations and critical appraisal of the data, a proposed layout including the sanitary units was drafted and is shown in figure 2.
Figure 2: Proposed layout of site
From the figure 2, it found that block B and C was located near to the labour camp and it will be more effective in terms of cost and mandays saved, when labours in block B and C uses the sanitation facilities in labour camps. It was evident that block A needs a sanitation facility, since labours in block A have to travel more and labour density was more in block A compared to others. By location technique, location for the portable sanitation was found out in 1st upper slab level. Thus it reduces the vertical movement of labours and time taken for use of sanitation facility. Table 1 shows the comparative analysis between existing facilities and proposed facilities. In this case, the weighted average of labour wages (including all trades) was found to be Rs. 350 per manday per labour. For the sample calculation, cost of portable sanitation facilities from locally available supplier was considered. Four additional portable sanitation unit and one urinal unit was proposed for the new proposed/ optimized layout as shown in figure 2.
Table 1: Comparative Analysis Table 2: Cost implications for sanitary units
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Table 2 shows the cost implications for sanitary units. It is proved that mandays saved to certain extent by the provision of portable sanitation near to work place in construction site. As time available increases the amount of work done in a given manday will increases proportionally with significant saving in the labour cost. Thus, portable sanitation leads to increased productivity by increasing the time availability and increased value addition for the labours because of timely completion of the project. Figure 3 shows the mandays saved and respective cost implications on different project which are in different phases.
Figure 3: Saving with respect to phases of construction
CONCLUSION:
This paper discussed the benefits of installation of portable sanitation facilities at construction sites. The location of the units are done by considering the space requirements, ease of access and supporting conditions for the portable sanitation. Moreover, the study proved to be beneficial as saving in time ultimately leads to the completion of a number of activities thereby reducing the indirect costs of the project. The health and safety of the workers was found to have improved due to cleanliness at the site which further leads to decrease in absenteeism rate. Further research can be carried out on location of portable sanitation facilities by using mathematical models and certain algorithms and software.
REFERENCE:
1. Chuck Henry, Elena Olsen and Marcos Fioravanti (2009), “Improving Sanitation With Composting Toilets, Bio Cycle International”, Feb 2009; 50, 2; J.G. Press, Inc.pg. 42.
2. Drewin, F.J. (1982), “Construction productivity: measurement and improvement through work study”, 1st ed., Elsevier Science Publishing Co., Inc.
3. El-Gohary, K.M. and Aziz, R. (2014), “Factors influencing construction labour productivity in Egypt”, ASCE, pp. 1-9.
4. Hanna, A. S., Taylor, C. S., and Sullivan, K. T. (2005), “Impact of Extended Overtime on Construction Labour Productivity”, Journal of Construction Engineering and Management, Vol. 131, pp. 734.
5. Oglesby, C. H., Parker, H. W., and Howell, G. A. (1989), “Productivity improvement in construction”, McGraw-Hill, New York.
6. Sweis, G. J. (2000), “Impact of conversion technology on productivity in masonry construction”, PhD Dissertation, Northwestern Univ., Evanston, Ill.
7. Thomas, H. R., and Raynar, K. A. (1997), “Scheduled Overtime and Labour Productivity: Quantitative Analysis, Journal of Construction Engineering and Management”, Vol. 123, pp.181.
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Received on 15.11.2015 Accepted on 19.12.2015 © EnggResearch.net All Right Reserved Int. J. Tech. 5(2): July-Dec., 2015; Page 317-321 DOI: 10.5958/2231-3915.2015.00044.9 |
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