Water damage to property following water heater explosion

Energy type: 
Natural gas
 
Event summary: 
Energy Safety was notified of an incident involving an internal flued water heater by Fire and Emergency New Zealand. There was water damage following the disconnection of a hot water pipe.
 
Accident ID: 
171023-01
 
Accident date: 
19 October 2017
 
Site: 
Commercial
 
Environment: 
Building
 
Voltage: 
1
 
Equipment: 
Water heater instantaneous
 
Accident type: 
Fire and explosion
 
Casualty: 
Non-fatality
 
Injury: 
No injury
 
Property damage level: 
No property damage
 
Outcome of investigation: 

There are two possible causes that Energy Safety can speculate on without further information:

  1. A foreign body was located on the burner of the water heater causing the water heater to ignite explosively. The hot pipe may have been disconnected by this explosion and this would have caused the burner to keep running while letting water into the property. This incident could have been caused by lack of maintenance.
  2. The hot pipe disconnected from the water heater for another reason, causing the water heater to work in the normal way, which could be considered out of control as water would have been entering the dwelling.

Energy Safety closed the event as one of the possible reasons for the incident is not a gas incident. It also may be due to lack of maintenance.