Civil Engineering Reference
In-Depth Information
Fire
Doors on the side walls of buildings
which are close to a boundary may
represent a risk of fire spread to
adjacent buildings. They are
classified, like windows, as
unprotected areas, and, in building
regulations, design limits need to be
placed on their use in these situations.
Outward opening external doors on
escape routes should be openable by a
simple device from the inside, and
electronically controlled locks should
fail safe (ie open) in the event of a
power failure, or alternatively should
be provided with a manual over-ride.
Certain doors will need to be fitted
with panic bolts.
ability to survive impact damage.
Maintenance
Doors which have very good
weathersealing, especially those of
timber with insufficient clearances,
tend to be very difficult to open
against their seals; close attention to
maintenance is needed if they are not
to become a nuisance (Figure 5.11).
BRE Digest 319
(199)
provides further
information.
For maintenance of finishes, see
the relevant section in Chapter 9.4.
Figure 5.9
This water bar is fitted in front of the jamb
rebate so that water running down is
directed to the interior
Work on site
Edge of section
should be chamfered
to direct water to
drain holes
Gr oove should be sealed at foot
Workmanship
The fitting of weatherstripping so as
not to create difficulties in opening
does need particular skill and care.
Noise and sound insulation
It is very difficult to improve the
performance of external doors to
more than around 30 dB(A), and
where this figure needs to be
improved upon, consideration should
be given to fitting a lobby. The use of
two doors either side of a lobby
should, depending on the absorbency
of the surrounding wall surfaces and
how well the walls are constructed,
give around
45-50 dB(A).
Inspection
The problems to look for are:
◊
Indoor
rain penetration - doors not suitable for
exposed situations
◊
no water bars or bars set in wrong
places
◊
no weatherboards
Outdoor
◊
warping of leaves
8 mm drain holes
◊
inadequate strength for security needs
Figure 5.10
Some proprietary trough sills may lead
water inwards
Durability
Doors made in earlier centuries from
softwoods such as European
redwood, although normally
classified as non-durable, have
proved to be remarkably durable in
practice, provided their paint finish
was regularly maintained. Some
whitewoods imported since the 1950s
have not proved so durable: typically,
painted but non-preservative treated
doors have suffered extensive wet rot
within around ten to fifteen years.
Such doors are now normally treated
with preservative.
The native hardwood, European
oak, is classified as durable and
resistant to treatment with
preservative. On the other hand,
while some imported hardwoods are
naturally durable, they may contain a
proportion of paler wood of less
certain durability, and they are now
normally specified to be treated
(155)
.
Durability of doors in other
materials is usually governed by
◊
no drainage channels
◊
non-safety glazing at low levels
◊
deteriorating lintels
◊
no weatherstripping
◊
finger traps in pivoting leaves
◊
automatic doors malfunctioning
◊
force required to open is too great
Figure 5.11
This compression seal set in an aluminium
section does not allow adjustment to ease
opening difficulties
