This research continues to clarify the relationship of transportation performance and drainage system of buildings. The situations of existing drainage system in buildings are the main issue and the investigation items would include the primary data and details of drainage system. As the results, totally 89 cases of existing buildings are added to be the objects of this research. The updated data are mostly corresponded to initial information of last stage investigation. Residential buildings are the majority of the investigation cases, the office buildings and some other types of constructions are included either. The slope of main drain with 1/100 is 60%, others include slope with 1/150 and 1/200. The size of main drain pipe is mainly ψ125 mm and ψ100 mm. The location of main drain of residential buildings is mostly in basement floor, some commercial and multi-utility buildings are set in ground or second floor to response the limitation of function plan.
This research initially focuses on the total length of main drain of existing buildings. The updated result is shown as Figure 2 which reveals the distribution of main drain total length with average 17.2 meter and standard deviation 10.5 meter. The cases data shows almost a normal distribution and the length is between minimum of 1.1 meter and maximum of 61.5 meter.
Figure 2. The distribution of total main drain pipe length
According to the empirical study above, 8 parameters are concluded to be the factors which affect the transportation performance of main drain in buildings. A simplified model was built to
Case number
Main drain length (m)
Average value 17.2(m)
estimate an approximate solid transportation distance by statistic methodology. Accordingly, 2 additional parameters including second elbow condition within the drainage system are added into the estimation model. A single regression analysis was adopted to conduct the calculation equation as the following.
ln： the affected length of individual parameter (cm) C： the empirical constant distance 769.7 (cm) e : the weighting factor
The estimated transportation distance is accumulated by the affected length of individual parameter. There are 8 parameters concluded in this research. Each affected length of individual parameter has a regression equation conducted from empirical validation.
4. Application tool and validation
The transportation distance of main drain in building is a complex issue which includes uncertain interaction phenomena of water and solid. Physical solution of fluid theory is still not clear nowadays. This paper proposed an empirical approach with simplified regression methodology from experimental results. The parameters which affect the transportation distance are concluded as 8 regression equations from experimental validation. In order to enhance the practical application of transportation distance calculation and verification, this research also developed an
interface of calculation software which can easily access by computer. The interface of calculation model is shown as figure 3 and a calculation case is shown in figure 4.
Figure 3. The interface of calculation model
Figure 4. A calculation case in model
It is known that the performance of solid transportation is one of the crucial issues in building drainage system. Water saving equipment directly reduces the volume of flowing water in the piping system which could affect the solid transportation distance. The use of saving water facility would increase the risk of solid transportation problems in drainage system. Due to the consciousness of sustainability, more and more existing residential buildings are refitted by saving water closet to reduce the water demand of daily utility. However, it often happened that the process with no checking the piping system conditions and that would be risky for drainage problem. It is necessary to clarify the relation of solid transportation distance and conditions of drainage system including flash water volume and piping system. According to the investigation results, this paper found some existing residential buildings with problems of main drain block. The conditions of the problem cases and the transportation validations are arranged as shown in Table 2.
Table 2 Problem cases and validation
Case
Age Floor Elbow Piping Slope Elbow Main drain Regulation Calculation No. height (V*) (D*) (H*) length(m) length(m) Distance(m)
The investigation obviously shows the crucial reason for the problem of main drain block. The main drain length of these cases is far longer than the regulation proposed length. Namely, it is proved that the ignored transportation performance of main drain really increased the risk of
sanitation problem. On the other hand, the validation results also reveal that the calculation distance highly corresponds to the regulation length of main drain in building. Due to the difficulty of
observation through real main drain function, this proposed estimation model and interface are practicable to confirm the drainage system design. Consequently, a regulation which can guide the designer and engineer to confirm the performance of drainage system and an empirical estimation model which can contribute the main drain confirmation are conducted and validated in this research.
5. Conclusion
This paper is one of the results from a long term research regarding transportation performance of main drain in residential buildings since 2006. The transportation distance of main drain is a complex issue which includes uncertain interaction phenomena of water and solid, however, the theoretical solution is still unavailable. As the results of this research, the current paper finished the investigation of present piping situation in existing buildings and the parameters category of solid transportation performance. Empirical approach was executed to clarify the solid transportation influence from these parameters. Eventually, this research conducted estimation interface to validate the solid transportation performance. This achievement can be used as an assessment tool for practical application. Therefore, a regulation which can guide the designer and engineer to confirm the performance of drainage system and an empirical estimation model which can contribute the main drain confirmation are conducted and validated in this research.
Acknowledgements
The authors would like to thank the Architecture & Building Research Institute of the Ministry of the Interior of Taiwan (ABRI) and the National Science Council of the Republic of China (NSC100- 2221-E-011-119)for financially supporting this research.
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