Post on 11-Jul-2015
TOPIC:Fire resistance, separating and fire- division walls,
fire escapes.
Walls, resistance to weather and damp.
Fire resistance and fire
escapesFire safety within a building is an extremely important issue. At the very least you should ensure that there is an adequate means of escape in case of fire, all measures and protective means will be in vain if there is no personal responsibility.
A fire escape is a special kind of emergency exit, usually mounted to the outside of a building or occasionally inside but separate from the main areas of the building. It provides a method of escape in the event of a fire or other emergency that makes the stairwells inside a building inaccessible. Fire escapes are most often found on multiple-story residential buildings, such as apartment buildings.
Common-style fire escapes
in Soho, New York City.
According to the occupation safety and health
Act 2006
“All means of escape from fire shall be properly
maintained and kept free from obstruction.
The contents of any room in which a person is
employed shall be arranged or disposed to provide
free passage way for the persons employed in the
work place shall not be locked or fastened in such
a manner that it cannot be easily and immediately
opened from inside.
In case of any workplace constructed or converted
for use as a workplace after the commencement of
this act, all doors which afford means of exit from
any building of the workplace for the persons
employed in it, shall, except in the case of sliding
doors, be constructed to open outwards.
Every window, door, or other exit which afford
means of escape in case of fire or giving access to
it, other than the means of exit in ordinary use,
shall be distinctively and conspicuously marked by
a notice printed in red letters of any adequate size.
In every workplace to which this act applies,
effective steps shall be taken to ensure that all the
persons employed are familiar within the means of
escape in case of fire, and with the routine to be
followed in case of fire.”
According to the Act "Section 704.5:
The fire resistance rate of the exterior walls with the fire
separation distance is greater than 1524mm shall be
rated for exposure to fire from outside. The fire
resistance rate of exterior walls with fire separation
distance (1524mm) or less shall be rated to exposure to
fire from both sides.”
You must carry out a Fire Risk Assessment .The overall
aim of a fire risk assessment is to reduce the risk of fire,
the risk of fire spread, and ensure that people can escape.
A fire risk assessment should systematically identify all fire
related hazards within the premises and analyze how
those hazards may adversely affect the building and its
occupants. It should identify the level of risk that those
hazards may present and also identify suitable control
measures for any significant findings. It is often best done
by a fire safety professional.
According to the Act “Section 705.2
Structural stability: Fire walls shall have structural
stability under fire conditions to allow collapse of
construction on either side without collapse of the
wall for the duration of time indicated by the
required fire resistance rating.”
Place signs detailing actions to be taken in the event
of a fire, make sure your residents and visitors know
how to react and where their nearest fire assembly
point is located, making sure that all residents are
able to understand any instruction provided.
According to the occupation safety
and health Act 2006
“In all workplaces subject to this act,
there shall be provided and
maintained, to be readily accessible,
means of extinguishing fire, which
shall be adequate and suitable
having regard to the circumstances
of each case.”
Goals and objectives of fire
resistance:There are generally four goals: life safety, property
protection, mission continuity and environmental
protection.
Life safety goals relate to protection of the building
occupants, and members of the public in the event
a fire occurs in the building. Life safety would
almost certainly be a goal in any very tall building.
Firefighter and first responder safety also need to
be considered.
Property protection relates to minimizing damage
to the building and building contents from fire.
Additionally, limiting damage to exposed buildings
would fit into this category.
Mission continuity goals address the impact on the
building and its tenants from fire. Some building
codes do not address mission continuity in very tall
buildings, although mission continuity might be
addressed for tenants who perform vital roles in the
community, such as hospitals and public safety
buildings. In most cases, the building owners,
tenants or their insurers will provide mission
continuity goals.
Environmental protection goals consider the
permissible impact on the environment from fire or
fire protection. Environmental protection goals
might address limitations on the types of fire
protection agents that can be used in a building
and the environmental consequences of a fire in a
facility which might release toxic products into the
atmosphere, ground water or bodies of water.
According to the occupation
safety and health Act 2006
“All stocks of highly
inflammable substances shall
be kept in a fire-resistant store
or in a safe place outside any
occupied buildings.
The store shall not be situated
in a way that endangers the
means of escape from the
workplace or from any part of
the workplace by persons
employed in it, in the event of
fire occurring in any part of the
workplace.”
Fire prevention and control services
include the following:
Sprinkler systems
Drenchers
Hydrants
Gas extinguishers
Fire alarms
Smoke, fire and heat
detectors
Electrical alarm
circuits
Pressurization of
escape routes
Walls, Resistance to Weather
and damp.Both the bricks and the mortar are porous. They will
absorb a considerable amount of water both from the
rain, and rising from damp ground by capillary action.
Modern brickwork relies on a damp-proof course to
prevent rising damp, and a drained cavity to resist
rain penetration. It is assumed that the whole of the
outer leaf will become damp in wet weather
conditions, and may have water running down both
faces in the case of wind-driven rain. Flashings and
built-in items are detailed to allow for this condition.
The damp-proof course is located
below the lowest timber or floor
(to keep these items dry), close to
the ground, but high enough that it
will not be breached by any proposed
or subsequent landscaping work.
Building codes specify suitable
materials for damp-proof courses,
which usually include bitumen-coated
copper and zinc, lead, and suitable
plastics.
The material must be flexible enough
to be racked up in the joints where the ground
level changes, and to remain intact across small cracks.
According to the Act in Physical Planning Act,
2010
“Every wall, floor and roof shall be constructed so
as to prevent any harmful effect on the building or
the health of the occupants caused by the passage
of moisture to any part of the building from— (a)
the ground; and (b) the weather.”
Filling the cavity below ground
When a brick wall extends below the ground floor, the
cavity is filled with mortar to ground level, struck off
with an outward slope. The damp-proof course is
located above the mortar controlling the use of land
generally.
This flashing, and the water
proofing under the slab, serve
as a damp-proof course to
prevent rising damp. However,
a layer of damp-proof material
may be used under the full
thickness of the inside leaf to
break bond, to avoid stresses
when the concrete shrinks and the brickwork expands.
Maintaining the cavity
Because the cavity is an essential part of the
weatherproofing system, the detailing must allow for
maintaining its integrity. A minimum cavity of 40-50
mm is considered essential to allow mortar droppings
to be observed and removed from ties and flashings.
If insulation is to be built into the cavity, it should be a
rigid board to avoid sagging, and held firmly against
the inner skin to maintain the minimum cavity width.
Flashings at floor level
Whenever a floor beam or slab crosses the cavity,
such as when both leaves of a non-load bearing wall
are supported at each floor level, a flashing and
weep holes are needed in essentially the same
configuration as a wall supported on a ground floor
slab.
Head and sill flashing
When it is necessary to close the cavity at door and window openings, the head and sill must be flashed (unless the head is so close under an overhang that it will not get wet). The head flashing extends far enough beyond the opening to throw any water clear of the jambs.
Limiting water absorption into
wallsWind-driven rain will penetrate a vertical face, which
will become damp and then dry out fairly uniformly
when the rain stops. Horizontal surfaces such as
parapets and sills absorb more water, and this tends
to penetrate into the wall below and dry out unevenly,
leaving unsightly wet patches for several days.
Therefore copings and flashings have to be designed
not merely to prevent water from entering the
building, but to shed the water from these areas to
limit the amount of absorption.
A coping like that shown in the diagram should have
drip grooves under each edge, to force water to drip
clear of the wall. If the material is waterproof (precast
concrete, or a metal sheet formed to a similar profile)
a dpm should not be required underneath it; but a
dpm is needed under a brick or stone coping
because it is porous.
Rising Dampness
Dampness within dwellings can take many forms.
True Rising Dampness is caused by a failure or lack
of an effective damp-proof course (DPC). Sometimes
a perfectly adequate damp-proof course is bridged by
high ground levels or blocked cavities resulting in a
similar pattern. Symptoms are generally damage to
decoration, breakdown of plasterwork and damage to
skirting boards and other joinery timbers. However, it
is possible for a property to be suffering from Rising
Dampness without some or any of these symptoms.
The minimum thickness and maximum height of
parapet walls should be as indicated in the diagram
above.
If the criteria indicated below cannot be attained
design calculations should be submitted to indicate
suitability.
Note, the information guidance on the left relates
only to structural aspects of parapet wall design.
Further advice should be obtained with regard to
moisture penetration.
Differences in level of ground or other solid construction between one side of the wall and the other should be less than 4 times the thickness of the walls.
References
1918 News article about an elastic canvas fire escape chute -- Keep a Fire-Escape Under the Window-Sill, Popular Sciencemonthly, December 1918, page 47, Scanned by Google Books: http://books.google.com/books?id=EikDAAAAMBAJ&pg=PA47
Biography for Abraham Wivell
"Fire Victims Slide Safely Down Tubular Chute" Popular Mechanics, February 1930
"Air Conditioner Installation". New York City Department of Buildings. Retrieved 30 June 2014.