Fire Extinguisher Safety Notice !!! Please Read.

The importance of have working fire extinguishers in our plants cannot be understated. The Aluminium Plant Safety Blog has posted incident after incident where proper use of a fire extinguisher was able to control a fire. On our tours around the globe we have seen hundreds if not thousands of fire extinguishers. On occasion we will glance at the inspection tag on a fire extinguisher. We look for the date of the last inspection. Making sure that the last inspection was within the last 12 months. If not we make sure the plant manager is aware. The following story deals with a safety notice involving a fire extinguisher model that we have seen in many aluminium plants. Here is the story:

'Norfolk Range' large dry powder fire extinguishers, manufactured before 2009, may be affected by moisture ingress at a threaded joint at the base of the unit, rendering the unit inoperable. The problem may not be identified during routine service inspections.

Users should identify if their extinguishers are likely to be affected. If yes and the extinguisher has been left exposed to adverse conditions since its last extended service, the condition of the elbow joint at the base of the unit should be examined by a competent service engineer.

If you are unsure if your extinguishers are affected by this safety alert, consult Britannia Fire Ltd.

Service engineers should closely examine, and if necessary, remove the elbow to confirm if there is evidence of water ingress to the discharge tube. If there is any doubt about moisture affecting the powder in the discharge tube, consider subjecting the extinguisher to an extended service including full replacement of the dry powder.

Introduction:

At a recent fire on a chemical plant, three wheeled dry powder fire extinguishers, containing 45kg of Monnex dry powder, failed to discharge when activated. This safety alert relates to dry powder units manufactured between 1970 and 2009. An identifying feature of these units is that the discharge hose is coupled at the base of the unit via a threaded metal elbow joint.

Photograph 1 shows the type of unit covered by this alert.

If you are unsure if your units are affected by this safety alert, consult Britannia Fire Ltd.

Background:

The units operate by opening a CO2 cylinder attached to the body of the extinguisher. The main body of the extinguisher holds the dry powder. The powder is discharged through a hose and is pushed out by the pressure of CO2. The units in scope of this alert have a discharge hose attached to the base of the body of the extinguisher by a piped metal elbow.

Photo 2: Rusted joint and caked powder from unit that failed to operate

HSE examined three of the above units that failed to operate. Each had rust visible on the inside of the elbow joints. The extinguishers had been kept outdoors under plastic covers and had been serviced every six months. The service engineers had noted the rust but it was not thought to affect the operation of the units.

The flexible discharge hose is normally removed during servicing however the elbow joint is not usually disturbed. It is believed that water ingress at this joint resulted in caking of the dry powder within the elbow joint. The caked powder may fall back from the discharge tube into the body of the extinguisher and so not seen during basic servicing. Upon activation of the extinguisher, the caked powder can block the discharge hose and render the unit inoperable.

Photo 3: Post 2009 model with discharge hose on top

Photograph 2 shows the rusted joint and caked powder from a unit that failed to operate. When the flexible discharge hose was removed the blockage was not visible. It was only identified when the elbow was removed from the body of the extinguisher.

The revised design of ‘Norfolk Range’ extinguishers produced by Britannia Fire Ltd is not affected by this problem. The design of the later versions features hoses mounted to the top of the unit, as shown in photograph 3.

Action required:

You should inspect any ‘Norfolk Range’ wheeled dry powder fire extinguishers and confirm if you have a unit with a discharge tube connected to the bottom of the unit.

If the extinguisher has been left exposed to adverse conditions since its last extended service, the condition of the elbow joint should be examined by a competent fire extinguisher service engineer.

Service engineers should closely examine, and if necessary, remove the elbow to confirm if there is evidence of water ingress to the discharge tube. If there is any doubt about moisture affecting the powder in the discharge tube, consider subjecting the extinguisher to an extended service including full replacement of the dry powder. Service engineers should advise clients to consider storing this type of extinguisher in a location where it is protected from rain or very damp conditions.

References:

BritanniaFire Ltd - Procedure for servicing and recharging Norfolk Range transportablefire extinguishers link to external website

BS 5306-3:2009 Fire extinguishing installations and equipment on premises. Commissioning and maintenance of portable fire extinguishers. Code of practice

Further information:

Britannia Fire Ltd, Ashwellthorpe Ind Estate, Ashwellthorpe, Norwich, Norfolk, NR16 1ER, tel: 01508 488416

website: http://www.britannia-fire.co.uk/ link to external website

The Health and Safety Executive had posted “Please pass this information to a colleague who may have this Product/ Equipment or operate this type of system/process.” We can assure the readers that on every future plant visit we will be asking about the plant’s fire extinguishers.

Our concern is that this safety issue has not been successfully put forth to all the aluminium plants in our industry. In addition we wonder if the HSE tested any other models? It would be our recommendation that if your plant has any other models made by this manufacturer that you request that the areas of clogging and rust formation listed above be inspected during your annual fire extinguisher inspection.

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