Cylinder Procedure PN376

Question 1

how are Cylinders constructed ?

Answer 1

Welded cylinders (two steel half so welded together around center)
Drawn steel (single steel skin containing no weld)
Aluminium cylinders
Composite cylinders

Question 2

What is a composite cylinder?

Answer 2

Woven”fabric” jacket impregnated with resin and protected by a hardened plastic outer cage. Occasionally theses cylinders have a aluminium inner lining

Question 3

Who supports the oic in there decision making process at these inc ?

Answer 3

Hazardous materials and environmental protection officer(HMEPO) they have received specific training for dealing with acetylene cylinders and hazard zone(HZ)management OIC should consult with the HMEPO at all cylinder incidents

British compressed gas association (BCGA) competent person
(BCGA CP)

Scientific Adviser-where appropriate

Question 4

Cylinders are at there greatest risk of failure when ?

Answer 4

When they have been subjected to flame impingement .
As a cylinder is heated the steel or aluminium shell loses its tensile strength (300 degrees for steel 200-250 for aluminium)

Question 5

When a composite cylinder is effected by direct flame impingement what could happen ?

Answer 5

The cylinder may become porous this is evident by a substantial increase in the size of the fire as it will be fed by the gas from inside the cylinder leaking out (designed cylinder safety feature)

When they have not yet become porous the fire can be extinguished and the cylinder cooled but left in situ as it might be in a weakened state and begin to leak when handled

Question 6

What should cylinders that cannot be identified as solely composite construction be treated as?

Answer 6

They should be considered as having a aluminium inner lining and treated as a steel cylinder

Be mindful that aluminium will fail at a lower temp therefore the cylinder may have already failed burning off the contents (HMEPO ) may advise gas dispersal techniques such as fine spray

Question 7

Why is the initial hazard zone (HZ) 200m ?

Answer 7

Fragments and in the case of acetylene the cylinder itself can be projected 200m also a fireball of up to 25m in diameter

Question 8

When on-route to a inc and the OIC becomes aware cylinders involved either by control or nature of premises on arrival tactics and considerations should be ?

Answer 8

Safe route of approach and subsequent position of appliances
Possibility of Acetylene being involved
Use of initial HZ overlay.
Surrounding risk may become involved if HZ implemented (railways major roads public buildings)
Early notification to BC of RVP

Question 9

As soon as a cylinder discovered at a fire the IC should?

Answer 9

Make every effort to extinguish any fire affecting the cylinder
cooling cylinder from behind substantial cover such as a suitable constructed double skin wall
attempt to Identify cylinder
If it hasn’t been affected then remove or cover with jets
Composite cylinders involved and failed contents allowed to burn off before extinguishing fire
Send cylinder informative message
Set up safe systems of work (SSOW) HZ zone

Question 10

When can the HZ be decreased ?

Answer 10

Following a DRA the IC can determine that
The fire has been extinguished
Cylinder not Acetylene
All cylinders located
Involved cylinders are receiving cooling (in the case of Acetylene after the first successful test in the cap test)

Question 11

What should be in the OIC messages from the inc after cooling cylinders?

Answer 11

Message stating the highest temperature recorded
Tactical mode
If the HZ still exist

Question 12

What are the visual indicators that a cylinder has not been involved ?

Answer 12

Paper labels and plastic ring still intact
Paintwork not blackened /blistered
supply hose still intact

Question 13

What should be considered when setting up a HZ ?

Answer 13

The time taken to implement compared with the time taken to cool the cylinder

Question 14

can crews work in a Hazard zone?

Answer 14

Yes a HZ is not a exclusion zone following risk assessment they must be behind substantial cover in full PPE, BA within 25m of cylinder

Question 15

What info should be in the OIC informative message ?

Answer 15

Actions taken 
The Number of evacuees
The HZ Size and road closures 
RVP and approach route 
Tactical mode

Question 16

Once a cylinder has passed the CAP test what should happen ?

Answer 16

Removal of HZ

Message stating highest temp HZ removed and tactical mode

Question 17

What is the cylinder assessment process ?

Answer 17

The recognised way of checking if decomposition is taking place is by the Wetting test in conjunction with a TIC (known as the CAP test)

Question 18

In situations where water cooling may have a detrimental effect on the inc what could be considered?

Answer 18

Air cooling ( known as self cooling) for a hour could be employed however only in consultation with the HMEPO as there may be a need for more frequent use of the CAP test and if a hot spot is identified then water cooling may be required

Question 19

HMEPO’s maintain a log a log at acetylene cylinder inc recording?

Answer 19

The location of the cylinder
When cooling commenced and is due to finish
When CAP’s have been carried out and temp readings
All decisions taken during the cooling process
Any requests for the CP and there subsequent advise and actions
Note this log must be handed over to any subsequent HMEPO at protracted inc where HMEPO no longer required then the OIC , the final OIC is to retain and send to initial HMEPO that attended

Question 20

When a cylinder is alight at the valve group the Flame can usually be extinguished and valve shut down what are the considerations?

Answer 20

Build up of un ignited gas if flame extinguished and valve not possible the shut down or leaking from neck
If cylinder has been heated then it should be cooled prior to attempting to shut down taking care not to extinguish flame.

Question 21

Why should a acetylene cylinder not be moved or disturbed until cooling process has been completed ?

Answer 21

If decomposition was all ready taken place within the cylinder then it will be sensitive to mechanical shock as any disturbance could cause fresh acetylene to enter the affected area and feed the decomposition process

Question 22

What are the procedures for dealing with cylinders not involved in a fire ?

Answer 22

They should be treated as hazardous materials inc, if it’s not possible to shut down cylinder then take precautions monitor the atmosphere consider requesting rotor FRU to monitor using DIM equipment
If a HMEPO has not been ordered than they should be requested via a priority message to BC

Question 23

If there is a doubt to who to hand the cylinder over to then ?

Answer 23

HMEPO can arrange collection via the British Compressed Gasses Association Competent Person (BCGA CP)

Question 24

When a cylinder is discovered unexpectedly the IC should ?

Answer 24

Set up a HZ (be mindful of the time this will take/ time to cool)
Make early contact with police for assisting in setting up HZ
Not put personnel at unnecessary risk e,g, appliance and equipment left in situ
Inform control

Question 25

When informing control what should info should also be in the message ? And why ?

Answer 25

What perimeter roads are closed, the RVP and Marshalling area for oncoming appliances
Reduces the risk of oncoming vechiles a from travelling into or through the intended HZ
The OIC should also be mindful of additional calls within the HZ and requirements of other agency’s and should consider the Forward Mobilising procedure

Question 26

When evacuating members of the public, what are the considerations ?

Answer 26

Liaison with local authority
Priority to public in close proximity to the inc
Those who are over 100m away who refuse to leave there should be every effort to inform them of the risks but if they refuse may be instructed to to temp shelter indoors away from doors and windows (for info purposes details passed to the senior police officer at scene )
Risk assessment for hospitals etc whether evacuation of patients will pose greater risk than leaving in situ
Close liaison with police and premises manager will ensure that maximum risk reduction reduction is implemented

Question 27

What I away to ensure that maximum risk reduction reduction is implemented in a HZ

Answer 27

Close liaison with police and premises manager will ensure that maximum risk reduction reduction is implemented

Question 28

What is the BCGA competent person?

Answer 28

Are designated personnel from various cylinder companies trained in the subject of acetylene in fires
The CP is available via emergency contact no’s stored within RM and on the cylinder hand over form on command units
It is not the role of the CP to instruct the IC on actions to be carried they are there to support the decision making process
They are only norm requested on difficult or protracted inc
They maybe able to offer advise on number of cylinders delivered to a premises

Question 29

How are composite cylinders constructed ?

Answer 29

In three layers
-gas barrier layer. (Typically a chem resistant thermoplastic in 1 piece)
-composite Layer (major load carrying layer reinforced with continuous fibre glass using a winding filament technology , UV resistant)
-outer layer (providing impact protection designed to be open to see LPG contents level
Note these type of cylinders are mainly for LPG domestic use e,g barbecues, patio heaters but can be found with various contents So if they are not being used for domestic purposes should be considered as having a aluminium liner and treated as such

Question 30

What are the designed safety feature of a composite cylinder?

Answer 30

Any meltdown of the thermoplastic inner liner & outer liner will allow contents to leak out through the robust glass fibre ‘cacoon’ in a controlled rather than catastrophic (BLEVE) fashion
LPG is heavier than air and will collect at low level unless affected by wind or other movement.

Question 31

What should you be aware of with composite cylinders in a fire ?

Answer 31

Composite cylinders melt at much lower temp and The release of release of contents through the porous jacket could initially cause significant increase in the intensity of the fire ( efforts should be made to protect surrounding area ) do not extinguish the fire as this will allow a cloud of LPG to be released creating a explosive atmosphere.
BE MINDFUL OF ALUMINIUM LINED CYLINDERS ! WHICH LOOK SIMILAR
Composite cylinders that can not be identified as solely composite should be treated as steel cylinder

Question 32

What are the risks of aluminium lined cylinders ?

Answer 32

They look the Same as composite cylinders however the aluminium layer will allow gas to escape if resin outer layer begins to melt the aluminium fails at lower temp to steel 200-250 degree therefore when involved will fail quickly and potentially catastrophically
Composite cylinders that can not be identified as solely composite should be treated as steel cylinder

Question 33

In assessing aluminium lined or solely composite cylinders in a fire prior to applying water, what should you look for ?

Answer 33

A simple observation of the nature of the fire should indicate if the fire is only the resin or is being fuelled by the contents. If the contents are escaping and burning of then allow to continue.

Question 34

How do you identify a acetylene cylinder?

Answer 34

Painted maroon over whole body ( acetylene only cylinder to not have a coloured shoulder)
Paper label attached to collar
Manufacturers are starting to fit retro-reflective tape or collars