By Joan Leedy, Technical Director

Maintaining fire protection systems onboard ships is critical to the safety of the crew as well as the cargo, ship and the environment. Maintaining a fixed dry chemical powder system is no exception. SOLAS describes testing and maintenance requirements for this type of system which includes the requirement to sample and test the dry chemical for moisture content, at a minimum of every two years.

The detailed requirements of this SOLAS regulation are described in the IMO document MSC.1/Circ.1432, para.8.2. This IMO document is entitled “Maintenance and Inspection of Fire Protection Systems and Appliances”

“These Guidelines apply to all ships and provide the minimum recommended level of maintenance and inspections for fire protection systems and appliances. This information may be used as a basis for the ship's onboard maintenance plan required by SOLAS regulation II-2/14.”

Section 8 of MSC.1/Circ.1432 is entitled “Two-year testing and inspection”. Section 8.2 describes the regulations for “Fixed dry-chemical powder systems” and the fourth item of this section states:

“4. test a sample of dry chemical powder for moisture content”

So why are the regulations concerned about the moisture content? If the content of moisture is high (0.25% is the maximum allowed), the powder can cake and not flow as designed—disabling the effectiveness of the system.  To accurately measure the moisture content of dry chemical, it should be sent to a qualified laboratory for testing.  

Additional Test Completed by Dyne Fire Protection Labs on Dry Chemical Samples

Chemical Type and Concentration - Dyne Fire Protection Laboratories identifies the dry chemical type and concentration—for example, whether it is potassium sulfate, sodium bicarbonate, ammonium phosphate, etc. Knowing the type and concentration of the active firefighting agent in dry chemical is key to ensuring it will work effectively for a specific hazard.

If you have any questions regarding this article, please contact Dyne Fire Protection Labs at or (800) 632-2304.

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