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2.7 _ The requirement
will be satisfied by following the appropriate design
guidance for each of the specialist activities, such
as:
a. _ School
or other educational establishment. Ventilation
provision can be made either in accordance with Table
2, except for sanitary accommodation where six air changes
per hour are required, or in accordance with the ventilation
requirements contained in the Education (School Premises)
Regulations. In spaces where noxious fumes may be generated
additional provision for ventilation should be made
and may require the use of fume cupboards designed in
accordance with DFE Design Note 29.
b. _ Workplaces.
Aspects relating to specific workplaces and work processes,
following the recommendations given in HSE Guidance
Note EH22 Ventilation of the workplace.
c. _ Hospitals.
The ventilation needed for various types of accommodation
will be different depending on the functional use of
the space; these values will also vary throughout the
year. The requirements are contained in the DHSS Activity
Data Base with general guidance and provision given
in Department of Health Building Notes appropriate to
each specific departmental area (eg HBN 4 Adult Acute
Wards, HBN 21 Maternity Departments and HBN 46 General
medical practice premises).
d. _ Building
services plant rooms. Provision for emergency ventilation
to control dispersal of contaminating gas releases (eg
refrigerant leak) given in paragraphs 25 to 27 of HSE
Guidance Note EH22 Ventilation of the workplace. Other
guidance in BS 4434: 1989. Specification for safety
aspects in the design, construction and installation
of refrigeration appliances and systems.
e. _ Rest rooms
where smoking is permitted. The Workplace Regulations
require that "Rest rooms and rest areas shall include
suitable arrangements to protect non-smokers from discomfort
caused by tobacco smoke". The following guidance
would satisfy this requirement:
_ _ i. natural
ventilation. Provision should be
_ _
made for both:
_ _
- an air supply in accordance with Table 2 for
_ _
an occupiable room; and
_ _
- the removal of tobacco smoke particles
_ _
through local extract ventilation.
_ _ ii.
mechanical ventilation. The design of the
_ _
ventilation system should prevent the
_ _
recirculation of air contaminated with tobacco
_ _
smoke. This could be achieved by extracting
_ _
the smoke-laden air to outside at a rate of
at
_ _
least 16 litres/second per person.
f. _ Commercial kitchens.
Guidance on ventilation provision is given in CIBSE
Guide B, Tables B2.3 and B2.11.
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2.8 _ The requirement
will be satisfied for car parks below ground level,
enclosed type car parks and multi-storey car parks if
there is for:
a. _ Naturally
ventilated car parks. The provision of well distributed
permanent natural ventilation, eg openings at each car
parking level with an aggregate area equal to at least
1/20th of the floor area at that level, of which at
least half should be in two opposing walls.
b. _ Mechanically
ventilated car parks, either:
_ _
i. the provision of both permanent natural
_ _ ventilation openings of not less than 1/40th
of
_ _
the floor area and a mechanical ventilation
_ _
system capable of at least three air changes
_ _
per hour; or
_ _
ii. for basement car parks, the provision of
a
_ _
mechanical ventilation system capable of at
_ _
least six air changes per hour; and
_ _
iii. for exits and ramps, where cars queue
_ _
inside the building with engines running,
_ _
provision should be made to ensure a local
_ _
ventilation rate of at least ten air changes
per
_ _
hour.
Alternative approach
2.9 _ As an alternative
to paragraph 2.8, the requirement will be satisfied
if the mean predicted pollutant levels are calculated
and the ventilation designed to limit the concentration
of carbon monoxide to not more than 50 parts per million
averaged over an eight hour period and peak concentrations,
such as by ramps and exits, not to go above 100 parts
per million for periods not exceeding 15 minutes.
2.10 _ Further
guidance can be found in Code of practice for ground
floor, mufti-storey and underground car parks published
by the Association for Petroleum and Explosives Administration
and in CIBSE Guide B, Section B2-6 and Table B2-7.
2.11 _ The requirement
will be satisfied if provision is made to protect the
fresh air supplies from contaminants injurious to health.
Air inlets for ventilation systems should not be sited
where they may draw in excessively contaminated air
(for example close to a flue, an exhaust ventilation
system outlet, an evaporative cooling tower, or from
an area in which vehicles manoeuvre).
2.12 _ Guidance
on design measures to avoid legionella contamination,
including design features not related to the ventilation
of the building, is covered in HSE's The control
of legionellosis including legionnaires' disease.
The relevant paragraphs are 71 to 89.
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