SCBA: checks, breathing air quality and cylinder testing

What the FSS Code requires

FSS Code chapter 3, paragraph 2.1.2, as replaced by resolution MSC.339(91)¹²:

• 2.1.2.1: a self-contained compressed air breathing apparatus with at least 1,200 l of air in its cylinders, or another self-contained apparatus able to work for at least 30 minutes. All air cylinders must be interchangeable.
• 2.1.2.2: an audible alarm and a visual or other device that alerts the user before the air in the cylinder is reduced to no less than 200 l.

MSC.1/Circ.1499 interprets the visual device: a pressure gauge that lets the user read that the air has dropped to no less than 200 l may count, “regardless of the need for supplemental lighting”.⁶

SOLAS regulation II-2/10.10.1.2, added by resolution MSC.338(91), makes SCBA in fire-fighter’s outfits meet paragraph 2.1.2.2 by 1 July 2019. Regulation II-2/1.2.5 applies this to ships built before 1 July 2012 as well, so every ship is now covered.⁴

Rule of thumb on capacity: free air is roughly the cylinder’s water capacity multiplied by its filling pressure. By this estimate a 6 l cylinder at 200 bar holds 1,200 l. At these pressures real air is less compressible than the estimate assumes, so the true content is a few per cent lower at 200 bar and noticeably lower at 300 bar. Use the maker’s figure for the rated air volume.

Spare charges and recharging

SOLAS regulation II-2/10.10.2.5 requires two spare charges for each required breathing apparatus. Cargo ships, and passenger ships carrying not more than 36 passengers, need only one spare charge per apparatus if they have a suitably located means of fully recharging the cylinders free from contamination.³ Passenger ships carrying more than 36 passengers built on or after 1 July 2010 must have a recharging means (regulation 10.10.2.6, added by MSC.269(85)). That is either a breathing air compressor of at least 60 l/min per required apparatus, up to 420 l/min in total, or a high-pressure storage system of at least 1,200 l per required apparatus, up to 50,000 l of free air.¹³

Drills use air too. SOLAS regulation II-2/15.2.2.6 requires either an on-board means of recharging the cylinders used in drills, or “a suitable number of spare cylinders”.⁴ MSC.1/Circ.1555 interprets this as at least one set of cylinders for each mandatory breathing apparatus, unless the safety management system requires more. A set is the number of cylinders needed to operate one apparatus. No extra drill cylinders are needed for apparatus required by regulation II-2/19 or the IMSBC, IBC or IGC Codes.⁷

The inspection cycle

MSC.1/Circ.1432 sets the minimum⁵:

Also follow the manufacturer’s maintenance instructions (paragraph 3.4).⁵ A practical weekly or monthly round, using the maker’s checklist, normally covers:

• the cylinder pressure on the gauge;
• the cylinder valve opening and a high-pressure leak check: close the valve and watch the gauge fall;
• the whistle sounding as the pressure is vented;
• the mask seal and the demand valve working;
• straps, harness and lifeline intact;
• the test date on each cylinder, including the spares.

Ships carrying chemicals or gas in bulk have stricter rules. Cyprus quotes paragraph 14.2.6 of the IBC Code: monthly inspection by a responsible officer, recorded in the log-book, and an annual inspection and test by an expert. Liberia applies the same monthly and annual checks to ships under the IGC and IBC Codes.⁹¹⁰

Breathing air quality

MSC.1/Circ.1432 paragraph 7.8.1 asks for an annual check of air quality from any on-board recharging system.⁵ Liberia specifies BS EN 12021, Compressed gases for breathing apparatus, or an equivalent standard acceptable to the class surveyor.⁹ Published summaries of EN 12021:2014 give these main limits¹¹:

Water matters on deck: moisture in high-pressure cylinders causes internal corrosion and can freeze demand valves in cold weather. Keep the compressor filters to the maker’s change intervals, site the compressor intake away from engine and boiler exhausts, and keep the air test certificate with the BA records.

Cylinder testing

• Steel: hydrostatic test every five years (MSC.1/Circ.1432 paragraph 9.4).⁵ Liberia and the Marshall Islands require the test date to be permanently marked on the cylinder.⁸⁹
• Aluminium and composite: “to the satisfaction of the Administration”.⁵ Flags usually follow the cylinder maker and the class society. Composite cylinders often carry a limited service life marked on the label, after which they are scrapped whatever their test results. Check the label at each inspection.
• New ships: Liberia and the Marshall Islands let the first five-year test be harmonised with the first special survey dry-docking if the cylinder’s first date stamp is not more than six months before delivery.⁸⁹
• Cyprus requires internal inspection and hydrostatic testing of SCBA bottles, including spares and the pressure vessels of the charging system, by a third party at intervals not exceeding five years. It also requires a third-party inspection of the apparatus every two years.¹⁰