RiskUKSeptember2017

FIA Technical Briefing: Gaseous Fixed Firefighting Systems
the strength of the pipes could lead to leaking
at the joints between each pipe, meaning that
the gas may not reach its intended destination.
On a more extreme scale, the pipe could
completely separate due to the pressure and
forces in the pipework that might well occur
during a system discharge, subsequently
turning that pipe into a projectile which would
then present a safety hazard.
Pipework and fittings may be suitable for one
type of gas system, but might not be suitable
for another. Fortunately, with the new
guidelines that we’ve created, it’s our intention
to assist in educating the industry and reduce
any confusion surrounding the pipework.
To be frank, we really need people to
understand that working with gas requires a
highly specialised set of skills coupled with an
understanding of how gas reacts and moves
within a pressurised environment.
The FIA’s guidance document goes on to
state that it’s ‘important that the pipework from
the container storage location to the protected
space is professionally installed by trained
personnel who have experience with the
installation of gaseous fixed firefighting
systems. They should also be fully conversant
with the manufacturer’s requirements to ensure
the integrity and stability of piping during
discharge and also aware of the forces
generated. Where agent storage containers are
located outside of the protected space, then
the pipe routing should be the shortest route
possible to the protected space.’
Building structure
Another factor to bear in mind with pipework is
the way in which the pipes are secured to the
building structure, which can cause further
issues if inappropriate pipe fixings are used
due to the high forces present when a system
discharges. As such, the pipework requires
supports that are fit for purpose.
The FIA’s guide duly notes that: ‘Pipe support
saddles or straps normally used for supporting
sprinkler system pipework may not be suitable,
as such supports might not be able to
withstand the forces generated by gaseous
fixed firefighting systems. The piping should be
securely supported to prevent any movement
under the reaction forces at pipe fittings during
the rapid filling of the pipework upon the point
of system actuation.’
The worse case scenario here is that the
piping could in fact come away from the wall of
the building. There have been instances where
this has occurred. The other Health and Safety
issue is simply that these pipes can be
extremely heavy and, if they were to fall down,
the consequences could be severe for anyone
unfortunate enough to be directly beneath the
pipework at the time.
All bases covered
Thankfully, the document contains a handy
chart for installers and designers of gaseous
fixed firefighting systems which gives the
measurements for the maximum spacing
between the supporting hangers, depending on
the nominal pipe size, which – with the correct
selection of the support – should prevent any
pipes from coming away from the wall and
causing any damage.
The guidance document covers everything
the designer or installer of gaseous fixed
fighting systems needs to know – the pipe
specification for both the actuation lines and
the pipework installation, methodologies for
connecting the pipes, how to join and seal the
pipes, what type of support to use to fix the
pipes to the structure, how to avoid corrosion,
marking, earth bonding and testing of the
completed pipework installation.
Robert Thilthorpe:
Technical Manager at the Fire
Industry Association
“Pipe threads that don’t match, improper seals between
pipework carrying the gas, corrosion and using pipes of
the wrong size or wall thickness could all lead to the
overall detriment of the system”
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