TECHNICAL BULLETIN 230: 2009: 1
Protection of roof
spaces, floor and
ceiling voids
TB230.1
SCOPE
The requirements of this Technical Bulletin shall be used as an alternative to
BS EN Clause 5.4 when providing protection to floor voids, ceiling voids and roof spaces
but excluding voids or spaces used as part of a smoke and heat control system .
TB230.2
TB230.2.1
DEFINITIONS
Cavity barrier
A separating element that resists the passage of flame, heat and fire gases for a period
of 30 minutes when evaluated to BS 476-22.
TB230.2.2
Air conditioning plenums
An unoccupied space, typically a ceiling void, in which air is moved or circulated
throughout the confines of the space at above or below atmospheric pressure, for
heating, ventilation or air conditioning purposes.
TB230.2.3
Smoke and heat control systems
Arrangement of components in a building to limit the effects of smoke and heat
from a fire .
TB230.3
TB230.3.1
ROOF SPACES, FLOOR AND CEILING VOIDS
Concealed spaces such as roof spaces, floor or ceiling voids
Concealed spaces such as roof spaces, floor or ceiling voids (between floors) shall be
'
protected appropriately as follows:
(a)
TB230.3.2
concealed spaces 0,8m or less in depth shall be:
(1)
sprinkler protected; or
(2)
compartmentalised by vertical cavity barriers which shall enclose areas no
greater than 250m2;
(b)
concealed spaces more than 0,8m deep shall be sprinkler protected ;
(c)
concealed spaces which vary in depth shall be either:
(1)
sprinkler protected throughout the communicating space; or
(2)
sprinkler protected throughout the sections greater than 0,8m in depth, with
the sections 0,8m or less in depth compartmentalised with vertical cavity
barriers which shall enclose areas no greater than 250m2.
Ceiling integrity
Where sprinkler protection is provided at the ceiling level , it is essential that there should
be no openings in the ceiling that provide communication between the room below and
the void through which the fire may be transmitted in the incipient stages.
TB230: Page 1 of 2
TECHNICAL BULLETIN 230: 2009: 1
TB230.4
TB230.4.1
CONCEALED SPACE PROTECTION
General
Where protection of the hazard is to TB222: Ordinary Hazard Group 3 protection using
Enhanced Protection Extended Coverage sprinklers, the protection in the concealed
space shall be to TB223.
For all protection other than EPEC, the protection in the concealed space shall be to
Light Hazard (LH) when the main hazard is LH , and OH1 in all other cases and pipework
arrangements shall be in accordance with BS EN Clause 17.3.
TB230.4.2
Ceiling air conditioning plenums
Where ceilings voids are used as plenums for ventilation or air-conditioning systems,
protection shall be provided both below the ceiling and within the ceiling plenum void and
the following requirements shall apply:
TB230.5
(a)
the plenum shall be protected by a suitable automatic fire detection system
complying with BS 5839-1 and BS 6266 as appropriate; operation of the ceiling
void fire detection system shall automatically shut down the plenum ventilation
system;
(b)
sprinkler installation pipe sizing shall be determined using the fully calculated
method;
(c)
the sprinkler area of operation shall be assumed to be the lesser of:
(1)
the area of operation stated in BS EN Table 3 plus four sprinklers in the
plenum void; or
(2)
the area of operation stated in BS EN Table 3 plus the number of sprinklers
in the plenum void;
(d)
sprinklers beneath the ceiling shall have a 'quick' response thermal sensitivity
rating; and
(e)
sprinklers located within the plenum shall have a 'standard' response thermal
sensitivity rating.
PUBLICATIONS REFERRED TO
'
•
BS 476-22 : Fire tests on building materials and structures. Methods for
determination of the fire resistance of non-Ioadbearing elements of construction.
•
BS 5839-1 : Fire detection and fire alarm systems for buildings. Code of practice
for system deSign, installation, commissioning and maintenance.
•
BS 6266: Code of practice for fire protection for electronic equipment installations.
TB230: Page 2 of 2