3 Potential Causes of Storage Water Heater Explosions
3 Potential Causes of Storage Water Heater Explosions
Background - Cote D'Azur Incident
On a seemingly ordinary Saturday, the tranquility of the Cote D’Azur condominium in Marine Parade was shattered. The Singapore Civil Defence Force (SCDF) received an urgent call for assistance at 70 Marine Parade Road, where a storage water heater ruptured in a fifth-floor unit. The explosion was so forceful that it shattered glass doors and windows of the balcony, sending shards flying across the area. This incident underscores the importance of proper engineering, maintenance, and installation of storage water heaters to prevent similar disasters.
Understanding the Engineering of Storage Water Heaters
A storage water heater consists of an insulated tank that holds and heats water until it is needed. It operates under pressure, meaning it must be equipped with multiple safety features to prevent overheating and excessive pressure buildup. Key safety components include:
- Pressure Relief Valve (PRV): Automatically releases excess pressure if it exceeds a safe threshold.
- Thermostat: Regulates temperature and prevents overheating.
- Check Valve: Prevents backflow and pressure imbalances.
If any of these components fail or are improperly installed, pressure can accumulate beyond the tank’s design limits, leading to catastrophic failure.
Potential Causes of the Explosion
1. Heater Drainpipe Improperly Terminated by an Aircon Contractor
A storage water heater requires a properly installed and unblocked drainpipe to safely discharge excess water and steam. If this drainpipe is mistakenly terminated, sealed, or redirected by an aircon contractor unfamiliar with plumbing requirements, the PRV may fail to release excess pressure effectively. This could lead to continuous pressure buildup inside the tank, eventually causing an explosion.
2. PRV Blocked with a Threaded Stopper to Stop Dripping
A PRV is designed to release pressure when it exceeds safe operating limits. However, some homeowners, perceiving a dripping PRV as a nuisance, may seal it with a threaded stopper or other blockages. This dangerous modification prevents the valve from performing its intended function, leading to pressure accumulation that may exceed the tank’s tolerance, potentially resulting in a rupture.
3. PRV Not Installed
In some installations, particularly when done by unqualified workers, a PRV may be omitted altogether due to negligence or cost-cutting. Without a PRV, there is no controlled release of excessive pressure caused by thermal expansion. Over time, the tank may reach its structural limits and explode due to the unrelieved internal force.
4. Using a PRV That is Not Rated for the Water Heater
A PRV must match the specifications of the storage water heater. If an incorrectly rated PRV is used, it may either fail to open at the required pressure threshold or open too frequently, leading to rapid wear and eventual failure. Either scenario increases the likelihood of uncontrolled pressure buildup, posing a severe safety risk.
Engineering-Based Preventive Measures
To prevent storage water heater failures, the following precautions should be taken:
1. Use Only Water Heaters with a Recognised Safety Mark
Purchase a storage water heater with a Safety Mark certification, ensuring compliance with industry safety standards. Certified heaters include all necessary safety components, such as PRVs, thermostats, and check valves.
2. Professional Installation by a Licensed Plumber
A licensed plumber should install the heater to comply with PUB (Public Utilities Board) regulations. Proper installation ensures:
- The PRV is correctly fitted and fully operational.
- The discharge pipe remains unobstructed and leads to a safe drainage area.
- All electrical and plumbing connections are compliant with safety standards.
3. Never Block or Tamper with the PRV
A dripping PRV should be investigated and replaced if faulty, rather than blocked or sealed. Persistent PRV discharge may indicate excessive pressure in the system, which requires attention from a qualified professional.
4. Conduct Regular Maintenance Checks
Routine inspection and servicing are crucial for safe water heater operation. Maintenance should include:
- Manually testing the PRV by lifting its lever to confirm it releases pressure.
- Checking for corrosion or rust on the tank, which may weaken its structure.
- Ensuring the thermostat is functioning correctly to prevent overheating.
5. Avoid Unqualified or Unlicensed Workers for Repairs
Entrusting installation or repairs to an unlicensed handyman increases the risk of safety violations. Licensed professionals adhere to PUB and EMA (Energy Market Authority) safety regulations, ensuring all critical safety components function correctly.
Conclusion
While storage water heater explosions are rare, they can have devastating consequences when safety measures are ignored or tampered with. The Cote D’Azur incident serves as a warning about the risks of poor installation, lack of maintenance, and unqualified repairs.
To safeguard your home:
✅ Purchase water heaters with a Safety Mark certification.
✅ Ensure installation is done by a licensed plumber.
✅ Verify that the PRV is correctly installed, unblocked, and functional.
✅ Conduct routine safety inspections.
✅ Never tamper with pressure relief systems.
By following these engineering-based safety precautions, homeowners can ensure their storage water heaters operate safely for years to come. Never compromise on safety—protect your home and loved ones.
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