Bacterial growth and even burst water tanks are hidden dangers in strata properties. Irregular maintenance and cleaning can cause the growth of micro aquatic bacteria which thrives in our warm Malaysian weather. Moreover, the lack of inspection can cause burst water tanks which not only escalates inter-floor leakages but also endangers building residents. Management Committees (MCs) must play a proactive role by raising awareness, advocating for regular inspections, and enforcing maintenance and cleaning protocols to safeguard the collective well-being of strata property owners.
As experts specialising in the inspection of water tanks and inter-floor leakage, we pay extra attention to tell-tale signs and inherent risks of water damage. One of the most dangerous inter-floor leakages that can happen in stratified buildings is the bursting of water tanks, which can flood buildings within seconds.
Furthermore, the location of the water tank plays a pivotal role, as a substantial volume of water can generate force, calculated as Momentum = Weight x Velocity. This force, augmented by the weight of water (1000 kg/m3), can fracture concrete pillars and reduce solid brick walls to rubble.
Major incidences of water tank bursts in Malaysia
Burst water tanks are not an unfamiliar occurrence in Malaysia. In a conversation with a former Commissioner of Buildings (COB), it was revealed that smaller-scale incidents of water tank bursts have been happening regularly, but without causing significant damage or casualties.
However, recently reported cases involving the bursting of huge water tanks have received considerable attention.
1. Taman Mas, Sepang
On 28 Oct 2022, a water tank located at a height of 18.3m (60 ft) in an apartment block burst, resulting in extensive damage to six vehicles. Source: Astro Awani.
2. SMK Melor, Kota Baru
On 9 August 2022, at least two students of SMK Melor were injured and three others were traumatised when the school’s water tank burst. Source: NST.
3. Terumtum Complex, Kuantan
On 23 July 2017, a water tank on the fourth-floor burst and flooded the area, and the collapsed wall had debris falling on cars and motorcycles. Source: Bernama.
4. Pangsapuri Cheras Utama, along Jalan CU 4A, Cheras
On 2 May 2017, a water tank (32,000 gallons) atop the 12-storey apartment block burst and damaged 12 apartment units, sending broken concrete slabs crashing to the ground. A Proton Wira and a motorcycle parked below were also damaged. Source: The Sun Daily.
5. Kamping Terus Teritip, Kuala Perlis
On 28 August 2015, two houses were damaged when gallons of water burst from one of the main water tanks in Kuala Perlis at 8.15 pm. Source: NST.
Disturbing and traumatising finds in water tanks
A haunting incident related to water tanks involves an unknown foul smell attributed to a corpse discovered in a condominium in Bukit Damansara on 15 May 2015. Reports indicated that an intoxicated man fell into the water tanks, remaining undetected for five days until the foul-smelling water was noticed, and a complaint was lodged with the Management Committee (MC). The revelation left residents traumatised when they realised that they’d consumed and showered with contaminated water.
Water storage tanks are basic utilities in stratified buildings, ensuring a consistent supply of domestic water. However, recurring incidents of burst water tanks have raised concerns among authorities and the general public. Perhaps it is time to look into the possible causes behind such occurrences and explore preventive measures.
Water storage tanks are basic utilities in stratified buildings, ensuring a consistent supply of domestic water. However, recurring incidents of burst water tanks have raised concerns among authorities and the general public. Perhaps it is time to look into the possible causes behind such occurrences and explore preventive measures.
How do water tanks get contaminated?
Water tanks which are do not have regular cleaning and maintenance schedules will experience the following:
- Corroded pipe fittings
- thick sediment build up on the bottom of the tank (this includes rust and interior coating particles)
- debris and dirt build up in the water outlet pipe
The danger here is that this excess sedimentation serves as a food source for pathogenic microorganisms. The longer sediment remains in a tank, the greater the risk for bacterial growth and water contamination.
Moreover, dead rats, snakes, foxes and birds can pollute the water – these animals may access the tank via damaged vents; holes or gaps in the water tank roof and shell; floor or roof hatches that were not properly sealed. These animal carcasses also serve as a host for pathogenic micro-organisms viruses.
The different types of water tanks
There are two primary types of water tanks – small and portable tanks, and larger tanks found in high-rise buildings.
Small and portable water tanks are typically made with polymer resin, reinforced with fibres, high-density polyethene (HDPE) or stainless steel. Larger water tank in high-rise strata buildings includes reinforced concrete tank, which incorporates food-grade waterproofing or HDPE liners, and/or in-site assembled water tanks with hardened mild steel panels or fibre-reinforced polymer riser panels.
These panels are secured using galvanised or stainless-steel bolts and nuts, reinforced by structural tie rods, brackets and sidebars, rubber gaskets, and/or HDPE liners.
Factors contributing to water tank degradation and failures
To ensure sufficient gravitational force for the distribution of domestic water across different floors, water tanks are typically positioned on rooftops. However, a majority of water tanks lack protection against degradation agents such as:
- ultraviolet rays (damage as consequence of exposure to light in conjunction with an oxidizer – such as air)
- heat and moisture
- biological exposure
- microorganisms growth (acidification of water)
When it comes to polymeric water tanks, such as fibre-reinforced polymer tanks, HDPE tanks, and other plastic components like rubber gaskets and HDPE liners, the degradation rate depends on the quality and additives in the polymer resin, as well as the reinforcement fibres. Furthermore, the intensity of ultraviolet, heat, and precipitation resulting from climate changes have worsened the situation.
On the other hand, metal water tanks featuring stainless steel or galvanized steel panels, along with other metal components, are susceptible to corrosion caused by changes in surface potential resulting from dents, scratches, and impacts.
In poorly ventilated areas housing water tanks, the presence of excessive chlorine gas can lead to the formation of hydrochloric acid on the metal parts when condensation occurs at night or during rainfall. This acid is detrimental to the metal components as it accelerates pit corrosion/rust, and can lead to cracks in these components.
Consequently, the compromised tensile strength of these rusty parts can result in localised failure and the rupture of the water tanks.
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Sedimentation is a process where heavier particles and debris settle at the bottom of water tanks, forming a layer of sludge. An excessive accumulation of sludge can increase the weight of the overall content significantly, and push water tanks closer to their fatigue rupture threshold.
Moreover, animals and insects that fall into the water tanks pose a serious threat to the cleanliness and hygiene of the domestic water intended for drinking and consumption. The growth of microorganisms that decompose such dead bodies can result in foul-smelling water and cause the acidification of the water, which can further degrade both metal and polymer tanks.
Concrete water tanks are designed in compliance with standards outlined in BS 8007, for the design of concrete structures to retain aqueous liquids, and the tolerance for serviceability crack width limit at only 0.2mm. Although such concrete structures are also susceptible to corrosion and degradation, signs of cracking and spalling prevail and are identified, preventing tank failure. Therefore, the likelihood of concrete water tanks rupturing is low, thanks to their inherent ductility.
Requirements for inspection and maintenance of water tanks in Malaysia
According to S85 of Street, Drainage, and Building Act 1974, the owner or the occupier of any building, or any part accessible to the public, shall be regularly cleaned and repaired, so that the building is free of any condition which may endanger the lives or health of its employees, members of the public and other users.
Similarly, the Strata Management Act (SMA) 2013 outlines that the management entities under different regimes – developer, Joint Management Body (JMB) and Management Committee (MC); shall keep and maintain the building in good repair, ensuring its safety and functionality.
Therefore, proactive measures to inspect and maintain water tanks in a safe and functional condition is of utmost importance, considering the possible safety hazards and consequences that could arise from water tank failures and bursts.
Clause C.4.2 in the Uniform Technical Guidelines in Water Reticulation and Plumbing, as established by the Suruhanjaya Perkhidmatan Air Negara, stipulates that shared water storage cisterns or tanks installed in high-rise residential buildings and gated communities shall be inspected and if required, cleaned and maintained at regular intervals on a voluntary basis.
Additionally, Kementerian Pembangunan Kerajaan Tempatan (KPKT) recommends that water tanks are cleaned annually to ensure the hygiene of domestic water and the safety of the water tanks.
Harnessing technology for efficient water tank inspection and cleaning
The inspection and cleaning of water tanks have often been perceived as costly, disruptive and labour-intensive. Conventional method in inspection and cleaning of water tanks requires the removal of water in the tanks, with downtime in water supply. Nevertheless, advancement in technology has introduced affordable solutions for both the inspection and cleaning of water tanks through the use of robotic devices.
One such innovation is the Remotely Operated Vehicle (ROV), commonly referred to as an underwater drone. It has enabled the inspection of water tanks without the need to drain the tank. Experienced ROV inspectors can swiftly identify abnormalities with ease. In cases where a close-range inspection is required, inspectors may even dive into the tanks for further investigation.
Additionally, robotic underwater vacuum cleaners minimise interruptions to water supply and reduce water loss. These devices can suck debris and sludge from the bottom of water tanks.
Strata property owners should educate themselves on the importance of water tank maintenance as they would have to keep their Management committee or JMB accountable. Frequent inspection is necessary to ensure the integrity of water tanks in strata residential buildings.
The insights highlighted in this article are co-written by two experts – Encik Sham Khaidzir, managing director of Satu Teknik Sdn Bhd, and Mr Kuan You Wai, managing director of PKN Building Solutions Sdn Bhd.