Civil Engineering Reference
In-Depth Information
believe this will meet the
requirements of the England and
Wales Building Regulations
Approved Document B
(52)
.
Glass in doors obviously has to be
strong enough to withstand everyday
use and slamming. Toughened or
laminated glass may need to be used
in glazed doors in some cases.
Glazing at low level is always a
danger for a child or adult. Glazed
doors should never be put at the
bottom of stairs.
Glazing
Glazing in all new doors in domestic
accommodation, and in all doors in
other building types, must be safety
glazing to BS 6262 up to a height of
1.5 m above finished floor level.
Annealed glass is permitted provided
the smaller dimension of the pane is
less than 250 mm.
Dampness and condensation
Although dampness in the outdoor
sense may not apply, there may
sometimes be a risk of condensation
from unheated areas, spillages of
liquids leading to conditions of high
humidity and some environments
having relatively high humidities
which have caused doors to warp.
In hospitals, for example, the
normal hygrothermal conditions
ranging from 25-65% RH over a
temperature range of 10-25 °C can
in some areas become 25-100% RH
over 10-30 °C. If these conditions
occur for any length of time on
either side of an unsuitable timber
door, warping can occur.
Dimensional stability, deflections
etc
For coefficients of linear thermal
and moisture expansion etc, see
Chapter 1.2.
Figure 8.6
A timber threshold to an internal door
Safety
Thresholds
With the increase of factory made
building components, such as
complete door sets, thresholds to
internal doors could become more
common. These may potentially be
dangerous and should be tapered off
unless a fitted carpet is used each side
of them (Figure 8.6). A
threshold associated with a change of
level is not so dangerous because the
change in height is visible.
access control over visitors, the main
entrance door to the flat may be the
only physical security measure
available to the residents. As such, it
has to be capable of resisting
prolonged attack by intruders using
tools, but also has to satisfy the
requirements for rapid entry from the
Fire Services.
The London Fire Brigade and Civil
Defence Authority require a door to
be capable of being breached in less
than three minutes using hand held
cutting tools. Police records indicate
that doors in the more vulnerable
estates, in this situation, have been
subject to uninterrupted attack by
intruders using sledgehammers and
proprietary jacks for periods of up to
30 minutes.
As a minimum, the doors and
frame should be of substantial
unglazed wood or steel
construction, to meet the
requirements of BS 8220-1
(69)
. They
must be fitted with hardware similar
to that specified for external doors
(see Chapter 5.1).
Using an escape mortice lock is
recommended, since it needs to be
locked with a key on leaving; this
reduces the danger of accidentally
locking a child in the flat. The lock
can be opened quickly by a simple
action from the inside without the use
of a key. BRE and DETR
Glazed doors
Glazing in doors is covered by
Approved Document N of the
Building Regulations
(186)
which
requires that glass in critical locations
should either:
●
break safely
●
be robust or in small panes, or
●
be permanently protected
If a door is glazed to the floor,
people may try to walk through it, and
in these circumstances clear glazing
should not be placed lower than 900
mm above finished floor level.
Obscured glass or a guard
rail at 900-1000 mm will help to
make the door obvious (although this
is not strictly a requirement under
Clause N2 of the Building
Regulations with respect to
dwellings).
Figure 8.7
Even this well fitting heavy door between a
Regency dining room and kitchen would
have required quiet servants. (The door is
shown slightly ajar)
