Wednesday 19 October 2016

Problem and Purpose Statement.

Problem Statement:

According to CP 48 (2005), high level water storage tanks in high-rise Housing & Development Board (HDB) flats store at least one day’s worth of water to cater to residents staying at the upper floors during periods of water supply disruption (see Figure 1). However, residents staying at lower floors continue to be affected by the disruption as their water supply comes directly from the main inflow pipe (see Figure 2).



Need therefore arises for the implementation of low level water storage tanks with a storage capacity of at least one day’s water usage requirement, in order for the residents staying at lower floors to be able to draw water reliably even during temporary water disruptions.

Purpose Statement:

The aim of this report is to propose to the Town Council the construction of two water storage systems, which will be located at low level. These twin tanks will have a combined storage capacity equivalent to one day’s water usage requirement for the residential block, and will be connected in parallel to supply water in a similar fashion to the existing high level water storage tanks, so as to maintain redundancy within the water storage system. This implementation will reduce the occurrence of water disruptions and improve the reliability of water supply for residents.

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Commented on Adam and Calvin blog post on 09/12/2016


Email sent to Prof for Consultation

Dear Dr. Moshood,

I am Ike Domenden, a first-year SIE (Building Services) student. As I am currently in Brad Blackstone's Effective Communication class, I have been assigned to a group of three including myself and tasked to identify an engineering problem and propose a solution. Following a discussion with Brad, I was told to seek your advice as you hold a great deal of knowledge with regards to Building Services matters.

The engineering problem that our group has come up with is the issue of water disruption in buildings due to cleaning and maintenance works being performed on their respective rooftop water storage tank.

From what we know, water storage tanks have internal partitions to ensure water output is not disrupted when one side is undergoing maintenance works. However, the partition warps over time, losing its watertight integrity. As a result, isolation becomes difficult to perform, and the tanks often have to be completely shut off in order to proceed with cleaning and maintenance works, leading to water disruptions.

To solve this problem, we are currently planning to propose the replacement of said tank into two individual physical tanks to ensure that isolation can be done effectively, so that any works being done on one of the tanks will not affect the overall water output.

Our group would like to consult you and obtain some background information on water storage tanks, so that we can have a better understanding before we prepare our proposal. The main items that we require clarification for are as follows:

1. Does every building have only one domestic water storage tank that serves water to the entire building?

2. Are different materials being used for water tanks? What are the pros and cons of each?

3. Is it better for us to focus on a specific type of building (HDB Flats, Shopping Malls etc.) when working on our proposal?

4. We plan to record an interview with experienced professionals or any relevant authorities, which we have identified as HDB, PUB, BCA and the local Town Councils. Which of these should we request an interview from in order to get a professional opinion on this matter?

We would really appreciate it if you could share your expertise with us regarding domestic water storage tanks. Alternatively, if needed, kindly assist us to direct these questions to the relevant people. Many thanks!

Best regards,
Ike Domenden
Sustainable Infrastructure Engineering
(Building Services)

Summary + Reader Response (Draft 3)

In the article “Trains on the North-South, East-West lines safe for service”, the Land Transport Authority (LTA, 2016) wrote that despite undergoing rectification works, the trains that have been in the media spotlight are safe for service. According to LTA, all new trains are tested before they are put into service. For defective trains, immediate action was taken to prevent defects from resurfacing during train operation. Hairline cracks that were discovered during inspection were confirmed to not affect operational safety. Nevertheless, to ensure that there are sufficient trains for commuters, all affected trains were sent back, one at a time, for rectification. Stringent checks would also be performed regularly to ensure operational safety of all trains. However, LTA should have made further investigation, if purchasing trains manufactured from CSR Sifang, is the most ideal choice.

Firstly, the article mentions that ‘these hairline cracks were due to localised impurity in the aluminium car-body material’, however, it fails to mention on the severity of the condition. “As one engineer put it, impurities in aluminium alloy is a catastrophic problem - in any industry. The structure may be sound initially, but its durability will definitely be compromised” (Tan.C, 2016). This proves that the trains may not have been the most ideal choice as the quality standard of the train is lowered due to the impurities in the material found in the train. CSR Sifang trains are the first batch of trains that have experienced this problem. “C151, the predecessor of C151A, has been manufactured by Kawasaki Heavy Industries in Japan since the 1980s. The two models share similar designs, but the C151 has been used by the SMRT since 1987 without experiencing cracks.” (Lai, M. H. S. 2016). Although ‘C151’ trains have been in service for more than 20 years, it has not experienced any cracks. Whereas the ‘C151A’ trains which has been in service for less than 10 years, has given so many problems till date.  In this case, CSR Sifang is not the ideal choice as the life span of the train is being compromised and the quality is not up to standard.

Moreover, the hairline cracks were not only the major issue caused by C151A trains. “On 17 December 2011, seven SMRT trains stalled on the North South Line causing the worst disruption in the entire SMRT history. The disruption across 12 stations from Marina Bay to Ang Mo Kio station lasted for at least seven hours, affecting at least 94,000 commuters” (Chew Hui Min, 2015). The main cause of this massive disruption is due to the stalling of the trains which had Current Collector Device (CCD) damaged. As the one of the engineer mentions that “the immediate cause of the stalling of the trains was damage to their Current Collector Device (CCD) “shoes” due to sagging of the “third rail” which supplies electrical power to the trains”. In this case, due to the poor quality of the CCD, it was not able to send the electricity signal to the train. As the report mentions “During both incidents, sections of the third rail sagged after multiple “claws” which hold up the third rail above the track bed, were dislodged”. This has caused a massive disruption that and proves that CSR Sifang trains are not the ideal choice of trains for service.

In conclusion, LTA should do their best to avoid these incidents from occurring and having a safe journey for its commuters. Although Singapore has ten of the best city train network in the world, these are some of the minor/major issues that may lower the standard of quality.

Chew Hui Min (2015, July 8) Power shutdown at North-South, East-West lines: Past major train disruptions. The Straits Times. Retrieved from http://www.straitstimes.com/singapore/transport/power-shutdown-at-north-south-east-west-lines-past-major-train-disruptions

Gwyn Topham. (2014, Febuary 18) Ten of the best city train networks – in pictures. The Guardian. Retrieved from 

Ministry of transport (2012). Report of the committee of inquiry into the disruption of MRT train services on 15 and 17 December 2011(Research Report). Retrieved from http://www.mot.gov.sg/news/COI%20report%20-%20Executive%20Summary.pdf

Land Transport Authority (2016, July 06). Trains on the North-South and East-West Lines Safe for Service. Land Transport Authority Press Room. Retrieved from

Lai, M. H. S. (2016, July 05). Secret Recalls: China manufacturer for MTR secretly recalls 25 SMRT subway trains after cracks found. FactWire News Agency. Retrieved from https://www.factwire.news/en/MTR-securetly-recall.html

Tan, C. (2016). Nothing routine about MRT cracks. Retrieved from

http://www.straitstimes.com/opinion/nothing-routine-about-mrt-cracks