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The
above title describes a specialised and intricate fire protection problem.
Today as more complex buildings are being built to a higher specification
the Fireplug Cable Passthrough System (CPT) has been individually designed
and then tailored to suit particular aspects of the changing demands of
today's specifiers.
The
CPT is a unit that can be used to allow a service that can be described
as temporary, such as a T.V. camera cable, to pass through a wall/floor
yet still maintain the integrity of the wall/floor as designated.
What is meant by integrity is that in a fire situation, you maintain stability
and insulation along with acceptable smoke stopping. These points
are also collated into designing a practical and sensibly operated system.
An
example of the type of building that lends itself to require a CPT system
is one that the general public frequent regularly, such as sports stadia,
concert halls, theatres, exhibition halls. Anywhere that people
congregate and where the media, like T.V. camera crews for example, need
to access right into the construction, trailing recording cable, lighting
cable etc. along with them. We trust the days have gone when a fire
door is propped open by an extinguisher (the alternative cable passthrough
system!). The following information is intended to prompt ideas
and ways of solving problems when you may not have been aware there was
any.
The most
simple CPTs can be seen on drawings 1, 2 and 3 and consist of two hinged
steel plates either side of the wall connected by a PVC pipe 160mm in
diameter. Surrounding the pipe is a fire retardant canvas smoke
sock with draw string end to pull tight around any services passing through.
Surrounding the smoke sock and PVC pipe and placed within the wall is
a Fireplug FPB intumescent pipe closer. In a fire situation, the
smoke sock stops the passage of cold smoke and toxic fumes, and under
the effect of heat, the intumescent pipe closer expands, crushes the pipe
and seals the hole through the wall.
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A non-fire rated wall passthrough (ref. CPTW) would not require the intumescent wrap or smoke sock.
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A ceiling
passthrough (ref. CPTC) is designed to allow access through a suspended
ceiling. Due to the thickness of the tile* it may not be possible
to fire protect at this point, however a smoke sock can be fitted to stop
cold smoke (see drawing 4).
*Ceiling types may vary, please contact us for advice.
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A Floor
Cable Passthrough, ref. CPTFRF (fire rated) and CPTF (non fire rated)
use exactly the same principle as the wall and ceiling CPTs. The
main difference here though is that at floor level, a rectangular access
is used, this makes blending in with the floor finishes neater e.g. tiles,
carpet etc.
The
CPT system is designed to protect against fire, heat and smoke.
In a fire situation the Fireplug FPB Intumescent Bandage will expand and
seal the opening against fire and toxic gases. It is with cold smoke
that the smoke sock comes into use.
When the month of the sock is closed down, using the pull string, the fire retardant foam closes around the cables slowing the passage of smoke.
Smoke socks can be supplied with pull string at each end for short CPTs, or effectively in two halves, one for each end of a long run.
When the month of the sock is closed down, using the pull string, the fire retardant foam closes around the cables slowing the passage of smoke.
Smoke socks can be supplied with pull string at each end for short CPTs, or effectively in two halves, one for each end of a long run.
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The smoke
Sock is made using a tough fire retardant fabric with a fire retardant
foam strip stitched around each opening. The foam acts as a further
smoke seal when closed around the cables.
The accountable
factors of the Cable Passthrough System have undergone the relevant testing
at FULMER YARSLEY to British Standard BS476, part 22, test No. J85007/1,
on 4th January 1990. Four CPTs were tested in the open position,
the test was terminated after 128 minutes.
Fireplug FPB Intumescent Fire Bandages have been tested by TRADA to British Standards BS476, part 20, test No. IT360, on 14th May 1993. Two hour insulation and integrity was achieved.
The Smoke Sock principle as yet does not have a test criteria. However prior to being used on the ICC Birmingham, both Birmingham City Building Control and Fire Brigade expressed their satisfaction that the acceptable level of smoke emission was attained.
Fireplug FPB Intumescent Fire Bandages have been tested by TRADA to British Standards BS476, part 20, test No. IT360, on 14th May 1993. Two hour insulation and integrity was achieved.
The Smoke Sock principle as yet does not have a test criteria. However prior to being used on the ICC Birmingham, both Birmingham City Building Control and Fire Brigade expressed their satisfaction that the acceptable level of smoke emission was attained.
The Cable Passthrough System, is covered by Patent, No. - 2 234 640 A.
The IFS
Cable Passthrough System takes care of breaching compartment walls and
floors. However there will be occasions when access is required
to take place within the building requiring several CPTs to be used by
the same cable. In order to make this feasible there is designed
a range of accessories that makes the routing of the CPT system efficient
and safe.
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On occasions
where the routing CPT has to be above ceilings or under floors etc., it
is obviously impracticable to remove tiles or flooring every time access
is required. The PVC ducting system in conjunction with the Cable
Passthrough System takes care of these problems and lets you take the
easy route.
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Detail showing
a pipe run routing through a suspended ceiling a two hour fire wall onto
another two hour fire wall. Above the suspended ceiling are pipe
support brackets made from tubular galvanised steel, connected by various
threaded fittings.
The galvanised
tube is welded to a half round metal plate (as under) and the bolts to
another half round metal plate claming the PVC pipe inside.
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The pipe
support brackets are extensively used where not in sight of the general
public e.g. above suspended ceilings as shown, inside acoustic voids or
generally back of house.
The PVC
pipe is supplied with a range of bends and joints as standard. One
important point is where movement or acoustic joints are crossed by the
pipe. Shown under is a typical movement and acoustic joint.
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Occasionally
the PVC routing will be of such a length (ICC Birmingham in excess of
30m), that it is impossible to feed the cables through by hand.
For this problem a pulley system can be installed while constructing the
routing. The pulley system is invaluable when CPT route passes through
floors to a level below and/or above ceilings or under raised floors.
The diagram shows a typical pulley system.
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To enable
routes to be planned by the user each CPT can be given an identification
number - details of which can be determined after the CPT system is in
use. A numbering sequence is useful when you can expect various
T.V. crews or perhaps helpers of different nationalities need to use the
CPT. Below is an example of a system installed at the International
Convention Centre, Birmingham.
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The PVC
routing system lends itself perfectly to carry beer lines on the same
principle as a temporary cable, only this time a beer line is more likely
to be permanent. Depending on the size of beer python a PVC routing
can be designed to accept more than one. The minimum and maximum
radius of the python is taken into account with access hatches built at
strategic intervals, as at every bend for example. The python being
more rigid than an ordinary cable is pushed along the routing from each
access hatch. Below are diagrams of some examples.
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The system
can be protected against fire and smoke in the same way as the Cable Passthrough
System e.g. Fireplug FPB Bandages, Smoke Socks, etc.
Where beer
pythons enter a building at ground level and there are higher floor levels
with bar facilities, there could be a need for a bank of python passthroughs
rising through the building. The number of pythons would decrease
as each level is reached. By clicking on the red link above you
will see a sketch of an actual beer python run found at the ICC in Birmingham.
At each floor level a steel python passthrough was fitted. For each
python there is a hinged steel lid which is closed when the python run
is not in use.
The PVC python ducting allows easy access to the beer lines and also protects the lines from attack from vermin, which is a real risk considering the areas in the building where beer pythons can be located.
The PVC python ducting allows easy access to the beer lines and also protects the lines from attack from vermin, which is a real risk considering the areas in the building where beer pythons can be located.