Foam Fire Fighting System

Foam fire fighting system servicing

Foam fire fighting system servicing covers the hardware of a ship’s foam installations: concentrate storage tanks, foam pumps, proportioners and inductors, valves, distribution piping, monitors, foam branch pipes, high-expansion generators and portable foam applicators. Foam systems protect tanker cargo decks, machinery spaces, cargo pump rooms, ro-ro and vehicle spaces and helicopter decks, where a fuel fire needs to be blanketed rather than cooled.

A foam system only works if the concentrate reaches the fire at the right mixing ratio. Proportioners that drift out of tolerance, seized valves and blocked nozzles are common, and are often found only during testing. This page covers the equipment. Laboratory testing of the concentrate itself is a separate service, foam concentrate analysis. vslSafety arranges both through suitable providers at the vessel’s port.

Regulatory requirements and standards

• SOLAS chapter II-2, regulation 10, sets where foam systems are required, and regulation 14 requires them to be maintained and ready for use.
• FSS Code chapter 6 covers fixed foam systems (high-expansion, and low-expansion in machinery spaces). It was replaced by resolution MSC.327(90), in force from 1 January 2014. It requires means for the crew to safely check the quantity of concentrate and take samples.
• FSS Code chapter 14 covers fixed deck foam systems on tankers.
• FSS Code chapter 17 and SOLAS regulation II-2/18 cover foam fire-fighting appliances for helicopter facilities.
• FSS Code chapter 4 covers portable foam applicators.
• MSC.1/Circ.1432 sets the maintenance and testing of foam systems, and MSC.1/Circ.1312, MSC/Circ.798 and MSC/Circ.670 cover the periodical control of low, medium and high-expansion concentrates.

From 1 January 2026, SOLAS amendments adopted by resolution MSC.532(107) prohibit the use or storage of fire-fighting foam containing PFOS. Ships built before that date must comply no later than the first survey on or after 1 January 2026, and removed PFOS foam must go to a shore reception facility. Where concentrate is replaced, the new product must be compatible with the approved proportioning equipment and mixing ratio, which may need maker or class confirmation.

Inspection and servicing intervals

Item	Requirement	Interval	Reference
Control and section valves, gauges	Check positions and pressure ranges	Monthly	MSC.1/Circ.1432
Portable foam applicators	Check in place and in proper condition	Monthly	MSC.1/Circ.1432
Concentrate storage tank	Verify correct quantity	Quarterly	MSC.1/Circ.1432
Pumps and sections	Flow test water and foam pumps; confirm flow in each section; flush with fresh water	Annual	MSC.1/Circ.1432
High-expansion piping	Blow through or confirm nozzles clear	Annual	MSC.1/Circ.1432
Foam concentrate	Periodical control test	Annual (first test not later than 3 years for most types)	MSC.1/Circ.1312, MSC.1/Circ.1432
Control valves, proportioners	Internal inspection; test mixing ratio within +30% to -10% of nominal	5 years	MSC.1/Circ.1432

What the service includes

• Review of system drawings, approval documents, foam type, mixing ratio and previous reports
• Visual inspection of tanks, piping, supports, valves, monitors and generators
• Functional testing of foam pumps, alarms, remote and local releases and fuel shut-offs
• Flow and pressure tests of water supply and foam pumps, and flow at each section
• Proportioner and inductor testing to confirm the mixing ratio, using a refractometer or conductivity method
• Blowing through of high-expansion piping, and nozzle and generator checks
• Internal inspection of control valves at the five-year service
• Fresh-water flushing of piping after testing
• Sampling of concentrate for laboratory analysis where requested

Equipment and system types covered

Providers work on tanker deck foam systems with monitors and hand applicators, high-expansion systems using inside or outside air in machinery spaces and ro-ro spaces, low-expansion machinery space systems, helideck foam units, and portable foam applicators. Proportioning equipment includes balanced-pressure proportioners, bladder tanks, in-line inductors, around-the-pump proportioners and water-motor driven proportioners. Makers encountered include Svenska Skum, FireDos and Minimax. Foam concentrates include AFFF, AR-AFFF, fluoroprotein, synthetic high-expansion and newer fluorine-free foams.

Common defects and PSC deficiencies

• Concentrate tank below the required quantity, or no means to check the level safely
• No valid foam analysis report, or foam known or suspected to contain PFOS
• Deck foam monitors seized, corroded or not rotating fully
• Proportioner not delivering the approved mixing ratio
• Valves seized or in the wrong position
• Piping left full of foam solution after testing, causing corrosion and blockage
• High-expansion generators damaged or ducts obstructed
• Portable foam applicator set to the wrong ratio for the concentrate on board

Certificates and documents you receive

• Service report covering inspections, flow tests and pressures
• Proportioner test results showing the measured mixing ratio
• Record of five-year internal valve inspection where carried out
• Defect list with recommended rectification
• Laboratory foam analysis certificate where samples were sent

How to prepare the vessel

Send the system drawings, foam type and mixing ratio, and the last service and analysis reports. Flow testing uses water and sometimes foam solution, so agree with the terminal or port where discharge is permitted and how run-off will be handled. Many tests can be done with water only, using conductivity or flow methods, to avoid wasting concentrate. Tankers should plan deck foam testing outside cargo operations. Keep enough concentrate on board, or arrange supply, to restore the required quantity after testing.

Information needed for a quotation

• Vessel name, IMO number, flag, class and ship type
• Port, ETA and ETD, and whether cargo operations will be in progress
• System types, makers and models, and protected spaces
• Foam concentrate type, maker, quantity and mixing ratio
• Last service date, last foam analysis date and five-year service history
• Whether foam replacement, PFOS disposal or new concentrate supply is needed

vslSafety coordinates a suitable provider at the vessel’s port. Foam systems are often serviced together with the wider fire fighting systems and equipment scope.

Frequently asked questions

How often must the foam system be tested?

MSC.1/Circ.1432 recommends monthly checks of valves and gauges, a quarterly check of the concentrate quantity, and an annual inspection that includes flow testing of pumps and sections, alarm tests and fresh-water flushing. Every five years the control valves should be inspected internally and proportioners tested to confirm the mixing ratio is within +30% to -10% of the approved value. Concentrate is tested separately in a laboratory.

What is the difference between foam system servicing and foam analysis?

Foam system servicing checks the hardware: pumps, valves, proportioners, piping, monitors and generators. Foam analysis is a laboratory test of the concentrate, checking properties such as sediment, pH, expansion and drainage under MSC.1/Circ.1312 or the circulars for medium and high-expansion foam. Both are needed, and a foam in good condition is of little use if the proportioner does not mix it correctly.

Do we need to replace our foam because of the PFOS ban?

Only if the foam contains PFOS above the permitted limit. Many older AFFF concentrates contain PFOS, while newer products usually do not. Owners should obtain a maker declaration or laboratory test showing the concentrate is PFOS-free. Where replacement is needed, the old foam must be landed to a reception facility, and the new concentrate must be compatible with the approved system.

Can the proportioner be tested without discharging foam?

Often, yes. Many proportioners can be tested with water in place of concentrate, measuring flows on both sides, or by conductivity methods with a small amount of concentrate. The method depends on the proportioner type and maker’s instructions. Testing without full foam discharge saves concentrate and avoids environmental problems in port.