Please note: this Class News is a reissue and replaces the version sent on 1 July, 2016. It has been amended to clarify the definition of automatic sprinkler and automatic water mist systems. 

The IMO has issued revised guidelines (contained in circular MSC.1/Circ.1516*) for in-service testing of automatic sprinkler and automatic water mist systems, following failures** that have been identified on both high and low-pressure systems. 

Automatic sprinkler and automatic water mist systems are those fitted with automatic sprinkler heads or automatic water mist heads (i.e. heads fitted with glass bulb actuators). They do not normally include automatic local water mist systems in engine rooms, which are usually open-nozzle systems automatically activated by the fire detection system.
 
The amended guidelines advise shipowners, operators and system manufacturers to actively monitor and assess the effectiveness of automatic sprinkler and automatic water mist systems on a planned periodical basis. This includes the following:   

• Water quality should be recorded and maintained in accordance with manufacturer guidelines.
• Quarterly testing and inspection should now include water mist, water spray and sprinkler systems water quality.
• Instead of annual functional testing of a minimum of two sprinkler or water mist nozzles, a new test regime has been included to ensure that all different types (according to manufacturer model) of sprinkler heads and nozzles are tested. The results of the initial tests can lead to extended testing.
• When testing using the new flow chart regime, water quality testing should be conducted in each corresponding piping section. 

Sprinkler system functional testing should only be carried out by personnel capable of ensuring the system is fully charged and operational after the testing, which will normally be the system’s manufacturer.
 
Sprinkler functional testing is to be witnessed by a Surveyor, preferably at the same time as the Passenger Ship or Cargo Ship Safety Survey.
 
* This amends circular MSC.1/Circ.1432 – Revised Guidelines for the Maintenance and Inspection of Fire Protection Systems and Appliances
**The failures (noted in MSC.1/Circ.1493) occurred on ships over five years of age and involved one or more of the following modes of failure: 

• blockage of the internal filters of the sprinkler heads with mineral deposits;
• build-up of scale and mineral deposits on the internal components of the sprinklers causing seizure when the sprinkler was activated; and
• corrosion of the internal components of the sprinklers causing seizure when the sprinkler was activated.