Design of Fire safety in Multi Occupancy Residential

Accommodation

Myth vs Reality

Myth. Fire is bright

Reality. It isn’t.

Flames are bright

Outside fires have bright

flames because of the

availability of oxygen and

because the products of fire

can escape

Myth vs Reality

Myth. Fires inside are dark

Reality.

Fire starts bright, but quickly

produces black smoke and

Complete darkness.

If you wake up to a fire you

may be blinded, disoriented

and unable to find your way

around the home you’ve

lived in for years.

Note the handprints along

the wall

Myth. You can

always outrun a fire

Reality. You can’t.

Fire can spread

extremely fast

In less than 30 seconds a small flame can get completely

out of control and turn into a major fire

Most fires in the home occur when people are asleep

Myth vs Reality

Myth. It’s only hot

near the seat of the fire

Reality. Hot gases expand

and rise very quickly

If this it what happens to

the plastic cover of an

emergency light...

The pressure inside the room

where the fire starts builds up

as the gases expand

Myth vs Reality

Myth. Fire doors are

an expensive waste

of time.

Reality. Early warning is

probably more important

but fire doors pay for

themselves as well as

saving lives

The owner of this property

doesn’t think they are an

expensive waste of time!

Myth vs Reality

Myth. Fire is deadly Reality. It isn’t a myth!

Although many more people die

from toxic fumes and inhalation

of super heated gases than die

from burnsRemember this ad

campaign?

Myth vs Reality

Current fire safety design has developed

from 2 separate pieces of Legislation

• The Building Regulations

• The Regulatory Reform (Fire Safety)

Order 2005 (The “Fire Safety Order”)

Legislation

Why two separate pieces of legislation to

deal with one hazard?

The Building Regulations deal with the design and construction of such developments.

The Fire Safety Order deals with fire safety issues in the common parts of all premises but does not apply to private domestic areas

Legislation

The Building Regulations• Means of escape

• Structural fire protection

• Surface spread of flame over

walls and ceilings

• Detection and alarm

• Access for the fire service

• All dealt with through Building

Control

Legislation

• Places a duty to carry out a risk assessment

• Make premises as safe as reasonably practicable

• Dynamic – changes depending on the risk

• Onus is on the ‘responsible person’

• Only applies to ‘common areas’ but will need to take in account risk generated in private areas

The Fire Safety Order 2005

Legislation

Why the need for fire safety regulation?

• Estimated 4 out every 5 house fires go unreported

• 55,800 reported fires in residential properties attended by Fire and Rescue Authorities in 2006

• 373 deaths

• 11,200 recorded injuries

Guidance

• Approved Document B

Volume 2 – Buildings Other

Than Dwelling Houses

• BS 9991

Fire Safety in the design,

management and use of

residential buildings

“Approved Document B

was developed for easy

and forgiving masonry

construction . .”

Approved Document B

Traditional Build

Approved Document B

Internal planning of flats

Approved Document B

Internal planning of flats

BS9991

Internal planning of flats –

Entrance from below

Smoke alarm

BS9991

Internal planning of flats –

Entrance from above

Smoke alarm

BS9991

Internal planning of flats –

Entrance from above

Heat DetectorSmoke alarm

BS9991

Internal planning of flats –

Consider this layout

Maisonettes with floor(s) at H>4.5m (Clause 9.5.2) Requirement for alternative escape(s) from non access level omitted

if either;

A protected stairway enclosure and an LD1 AFD system to BS 5839-6 subject to no floor >7.5 m above or below entrance level of maisonette); or

A protected stairway enclosure and domestic sprinkler coverage in accordance with BS 9251 or BS EN 12845 within the unit.

Flats with Galleries (Clause 9.6(e)) Additional limitation that gallery >50% of the area of the floor below

should be treated as an inner room – cannot be overcome by sprinkler protection in floor containing the gallery

Open Plan Flats• Single level only (and no galleries)

• Maximum 16m x 12m with an

enclosed kitchen

• Maximum 10m x 8m with an open (but remotely sited)

kitchen

• Minimum 2.25m floor to ceiling height

• Sprinklered (at least to BS9251)

• Fire detection and alarm to a LD1 Grade D standard

(self contained fire detectors in all rooms and corridor)

BS9991

Typical Layouts (2 bed)

10m x 8m

Open plan

Inner bedrooms

• Increased detection

• Sprinkler protection

BS9991

Typical Layouts (3 bed)

12m x 16m

AD-B compliant

Open plan

Inner bedrooms

• Increased detection

• Sprinkler protection

BS9991

General Requirements (Clause 5)

Permits the use of keys on escape windows and doors (advice to occupants) – not inferred in AD-B

Escape Windows / Doors (Clause 5.1(c))

• Min opening size 0.33m2 / 450mm as per AD B

• Cill of dormer or rooflight ≤1.5m (1100mm in AD B)

• refers to Table 1 of BS 6180:2011

BS9991

Private Balconies

Private balconies H<4.5m

• Enclosed balconies to be treated as

an inner room

• Where balconies are enclosed and

are contiguous with enclosed

balconies to other flats, the fire

resistance of the balcony structure

and compartmentation to be

maintained

BS9991

Private Balconies

Private balconies H>4.5m

• Escape through not more

than one access room

• Access room to be clearly

visible from balcony

• Travel distance limits for

single direction escape

BS9991

Communal Roof Gardens,

Balconies & Terraces

• Single direction escape of 45m

• No limit on travel with

alternative escape

• Protection of escape routes to

conform with the requirements

for either small buildings or

single stair buildings >11m

• Need to consider evacuation of

disabled where lift access is

provided

BS9991

No limitations on travel distance on deck approach but “all parts of the building need to be within 45 m of a fire main, measured along a line on which hose can be laid”

BS9991

Common Escape RoutesBalcony Deck Approach

Common Escape (Clause 7)

Balcony Deck Approach (Clause 7.3 & Fig 5) Minimum fire resistance of 30 min Walking surface to be imperforate Down-stands depths were width of

balcony is more than 2m between flats required( 0.3m-0.6m or be calculated).

Need to prove that balcony will not be smoke logged if less than 1.8m from the building facade and single direction of escape. Manual calculations acceptable

but CFD analysis may be most appropriate tool

Single direction of escape further safeguarded by external balustrade to be

imperforate. Wall, balcony soffit and balustrade

should be of a Class 0 rating.

Common Escape (Clause 7) Common Corridor Approach

(Clause 7.4) Single stair buildings > 11m

and multi stair building

Common Escape (Clause 7) Common Corridor Approach (Clause 7.4) Natural ventilation (Clause 26)

or Mechanical smoke control system option in lieu of cross-

corridor fire doors and natural vents in code compliant layouts.or

Mechanical smoke control system option may be considered to facilitate extended corridor solutions (quantitative comparative design required)or

If sprinklered throughout the block of flats (excl EC facilities),travel distances can be doubled on common escape (Clause 23.2)

7.5m → 15.0m30.0m → 60.0m

Common Escape (Clause 7)

Smoke Control in Common Corridors (Clause 7.4)

Refers to Clause 26 for details of smoke control requirements. Vent to stairs must be an AOV (1.0m2) (Clause 26.1.3)

Clause 26.1.3 (options a, b or c) all refer to requirements for common lobby / corridor

“immediately adjacent to the

stair”

NOTE 3 The shaded area indicates the area requiring a smoke control system.

Common Escape (Clause 7) Common corridor in multi stair

Common Escape (Clause 7) Common corridor in multi stair condition

Clause 26.1.4 refers to 26.1.3 for venting requirements. 26.1.3 specified corridor AOV of 1.5m2 / stair AOV 1.0m2. “however ...... vents to the exterior of the building may also be

manually operated..” (Clause 26.1.4) and 26.1.3 only refers to automatic venting over stairs

BS 9991

Ex Fig 7 of BS 9991

Common Escape (Clause 7)

Common Corridor Approach: Small Single Stair < 11m

(Clause 7.5 & Fig 8)

Criteria largely as per AD B

except for a few notable changes

Common Escape (Clause 7)

Common Corridor Approach: Small Single Stair < 11m(Clause 7.5)

Omits the requirement that ancillary areas and flats should not be on same floor level (Clause 12(b)(e))

Fig 8(b) design (two apartments per floor)

stair ventilation must be by means of an AOV and not OVs (Clause 26.1.2)

Not applicable to Open Plan living layouts (unless the lobby to the stair is maintained)

Extra Care / Special Housing (Clause 8)

Scope of BS 9991 code expanded to cover “extra care” and other special housing Max 9m travel within EC unit or provide alternative

escape. Max 7.5m travel from flat door to storey exit or cross corridor door retained

Need to consider “adequate refuge space” requirements in corridors / stairs

Evac lifts to BS9999: 2008 “where deemed necessary” Free swing / hold open devices to be used in common

circulation routes where self closers present an obstacle to movement

Extra care facilities to be sprinkler protected (Clause 23.1)

Mist Systems

Access for Fire Service (Clause 18-21) Vehicular Access – no internal fire main

(Clause 19.1.2)

Access to all parts of dwellings within 45m

(AD-B: Block of flats with no fire main requires access to within 45m of every point on the projected plan area to individual units)

Can be increased on foot of sprinkler protection and where arrival time of fire service is not more than 10mins

to 90m for houses (H<4.5m)

to 75m for houses / flats (not more than one floor above 4.5m)

Arrival time subject to consultation with Fire Service

Access for Fire Service (Clause 18-21)

Residential Fire Fighting Shaft (Clause 19.2)

Stair door to be FD60S

Apartment corridor to serve as

fire fighting lobby

Can use additional fire mains

in escape stair to meet

coverage requirements;

60m from outlet in fire shaft

45m from outlet in escape stair

Active Fire Protection (Clause 22-26)

Fire Alarm System (Clause 22) No requirement for common AFD system (Clause 22.1) other

than to initiate smoke control systems

Clause 26.2.3.4 “Unless a simultaneous evacuation arrangement is deemed appropriate, there should be no sounders attached to the smoke detectors within common parts. NOTE 2 The purpose of smoke detectors is to operate the smoke control system, not to raise an alarm”

Only non residential areas in mixed use buildings need have AFD fitted

Risk assessment approach considered appropriate in determine AFD requirements for communal areas / roof gardens associated with sheltered housing

Active Fire Protection (Clause 22-26)

Sprinkler & Watermist Systems (Clause 23)

Sprinklers recommended for Buildings > 30m (and possibly H>18m) – BS EN 12845 Extra Care developments

Sprinkler protection trade-offs (discussed already) 3 storey house with open plan ground floor (Clause 6.3) 4 storey house with no 2nd means of escape (Clause 6.4) Open plan flats (Clause 9.7) Increased distance vis vehicular access (Clause 19.1.2) Increased travel in common corridors (Clause 7.4) Reduced boundary distance by half (Clause 29.4.2)

Active Fire Protection (Clause 22-26)

Sprinkler & Watermist Systems (Clause 23)

Watermist gets conditional approval in BS9991 subject to agreement of the relevant enforcing authority (Clause 23.1)

Needs specific scenario testing to prove viability and effectiveness of each system

Active Fire Protection (Clause 22-26)

Manual Fire Fighting equipment (Clause 24)

Not required in common areas (unless risk assessment dictates otherwise)

Employed in “higher fire risk areas” in sheltered housing

Special Risk Protection (Clause 25)

“Where a common stair forms part of the only escape route from a flat, unless it is designated as a small single-stair building in accordance with 7.5, it should not also serve any covered car park, boiler room, fuel storage space or other ancillary accommodation of similar fire risk.”

At odds with 13.2 which permits sprinklered basement car park for single stairs buildings > 11m ?

Any Questions