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Intumescent protection
for ironmongery
» » RECENT EVENTS HAVE
brought an increased focus to
the subject of fire doors. Here,
Douglas Masterson, technical
manager at the Guild of
Architectural Ironmongers (GAI),
provides the answers to some
of our most frequently asked
questions on intumescent seals
and intumescent protection for
ironmongery on fire doors.
To meet the performance
requirements of a fire test, every
fire door assembly these days
must be fitted with an intumescent
seal. An intumescent material
expands under exposure to
intense heat. It is designed to fill
the normal gap between the door
leaf and its frame, blocking off
the supply of oxygen in this area
to slow down the rate of erosion
and charring of the timber. A
fire door must be a fully tested
door construction with all the
appropriate fire test evidence.
Retrofitting intumescent on to a
door blank will not make it a fire
door.
WHERE SHOULD THE FIRE
SEALS BE LOCATED?
Wherever possible, the seal
should be fitted in the door
frame, rather than the door leaf,
so that the door can be adjusted,
if needed, without needing to
remove and re-fit the seal.
WILL A STANDARD
INTUMESCENT FIRE SEAL
PROVIDE SMOKE PROTECTION?
No. The conventional door
stop on a fire door is inadequate
as a smoke barrier. A threshold
seal should also be considered
on a fire and smoke door if
there is a gap of more than
3mm at the threshold (this is a
recommendation of BS 9999 and
BS 8214).
CAN I SUBSTITUTE A
DIFFERENT INTUMESCENT
MATERIAL TO THAT WHICH
HAS BEEN FIRE TESTED?
Using a different seal could
have serious consequences on
the door’s fire performance. For
example, if the wrong seal is used
down the meeting stiles of a pair
of doors, it can expand with such
force that the door leaves can be
pushed open.
That said, intumescent seals in
third party accredited schemes
(such as Certifire) are warranted
for fire doors of certain types
and dimensions. From this data,
you could identify seals from
different manufacturers which
would be suitable for a specific
application.
WHICH PRODUCTS ON
A FIRE DOOR WILL NEED
TO HAVE ADDITIONAL
INTUMESCENT PROTECTION?
The essential ironmongery
often needs to have additional
intumescent protection. This
means hinges, lockcases
and concealed self-closing
devices which are all critical
to the operation of a fire door,
especially under fire exposure.
Intumescent pads can protect
hinge positions and various
thicknesses are available e.g.
0.5mm, 1mm and 2mm, all of
which will offer protection to a
greater or lesser degree. Likewise,
mortise lockcases and strikes, and
concealed self-closing devices
often need to be protected by
intumescent gaskets of the correct
material and dimension.
There are occasions when a
door assembly will pass a fire
test without using additional
intumescent protection. It is vital
that the test evidence is checked
with the door manufacturer.
‘designed
to fill the
normal gap
between
the door
leaf and
its frame,
blocking
off the
supply of
oxygen in
this area to
slow down
the rate
of erosion
and
charring of
the timber’
WHAT ARE THE FACTORS WHICH
SHOULD BE CONSIDERED WHEN
CHOOSING A SPECIFIC TYPE OR
SIZE OF INTUMESCENT STRIP
FOR A FIRE AND SMOKE DOOR?
• The fire resistance required
(30/60 minutes)
• The type of door (single/
double-leaf)
• The meeting stile detail (if
pairs of doors are involved)
WHAT SHOULD I SPECIFICALLY
LOOK OUT FOR REGARDING
INTUMESCENT MATERIALS?
• Performance claims for
intumescent material should
be carefully checked
• Valid documentary
evidence must underpin any
recommendation
• Is the material offered
as described on the test
document?
• Are the tests/assessments in
date?
I ALSO REQUIRE ACOUSTIC
AS WELL AS FIRE AND SMOKE
PROTECTION ON A DOOR
ASSEMBLY. IS THIS POSSIBLE?
Yes, this is a common occurrence
as the majority of acoustic doors will
also be required to act as fire and
smoke doors. Note that conventional
brush style smoke seal is not suitable
for acoustic doors whereas a fin seal
will perform in this application.
‘retrofitting
intumescent
on to a
door blank
will not
make it a
fire door’
LOCKSMITHJOURNAL.CO.UK | NOV/DEC 2018
Sponsored by ABUS
CAN YOU PAINT OVER FIRE
AND SMOKE SEALS?
Over-painting of intumescent seals
would not compromise performance
in a fire situation. However, the
flexible elements of smoke seals
should not be painted over as this
will certainly compromise smoke
containment performance. If the
smoke seal part of the seal has
already been painted over, it should
be replaced immediately.