amanbh997/skills-architects/fire-life-safety

Fire and Life Safety Design

This skill provides practitioner-grade knowledge of fire and life safety design for architectural practice. It covers the architect's role in fire strategy, compartmentation, egress design, structural fire protection, smoke control, and active fire protection systems. All dimensional values are metric with imperial equivalents where standard practice requires.

Section 1: Fire Strategy Development

The Architect's Role

The architect is the primary coordinator of fire strategy in building design. While fire engineers provide specialist analysis (computational fire modeling, structural fire engineering, smoke control design), the architect is responsible for integrating fire safety into the architectural concept from the earliest design stage.

Fire safety is not an add-on. Buildings that treat fire protection as an afterthought suffer from: compromised spatial quality (corridors widened at the expense of usable space), increased cost (fire-rated construction added where it could have been avoided by better planning), and occupant risk (egress paths that are long, confusing, or difficult to maintain).

Fire Safety Objectives

1. Life safety: Ensure all occupants can evacuate or reach a place of

safety before conditions become untenable. This is the primary objective and is non-negotiable.

1. Property protection: Limit fire damage to the area of origin or

a defined compartment. Relevant for insurance, business continuity, and heritage buildings.

1. Business continuity: Design systems to minimize downtime after a fire

event. Particularly important for: hospitals (defend-in-place), data centers, manufacturing, and critical infrastructure.

1. Environmental protection: Prevent fire-related contamination of soil,

water, and air. Relevant for: chemical storage, waste facilities, sites near waterways.

1. Firefighter safety: Provide safe access for fire service operations.

Firefighting shafts, wet/dry risers, fire command centers, adequate water supply.

Prescriptive vs Performance-Based Approach

Prescriptive approach:

• Follow code provisions directly (IBC, Approved Document B, NBC, etc.)
• Advantages: straightforward, well-understood, defensible
• Limitations: may be overly conservative, may not address novel building

configurations, does not account for specific building use patterns

Performance-based approach:

• Establish fire safety objectives, define design fire scenarios, demonstrate

through engineering analysis that objectives are met

• Methods: computational fire modeling (FDS, CFAST), evacuation modeling

(Pathfinder, STEPS, Simulex), structural fire analysis (FEA with fire curves), smoke control analysis (CFD)

• Advantages: can optimize design, accommodate complex geometries, provide

a more accurate risk assessment

• Limitations: requires specialist fire engineer, peer review, AHJ acceptance

Hybrid approach (most common):

• Follow prescriptive code for most provisions
• Use performance-based analysis for specific challenges: atrium smoke control,

travel distance extensions, reduced fire resistance periods, alternative egress strategies

Fire Strategy Report Content

A fire strategy report (also called fire safety strategy, fire engineering report, or basis of fire safety design) should include:

1. Building description: use, occupancy, construction, geometry
2. Applicable codes and standards
3. Design fire scenarios (size, location, growth rate)
4. Compartmentation strategy and fire resistance schedule
5. Means of escape: travel distances, exit widths, evacuation strategy
6. Fire detection and alarm design
7. Sprinkler/suppression system scope
8. Smoke control strategy
9. Structural fire protection specification
10. Fire service access and facilities
11. Building management fire safety provisions
12. Drawings: compartmentation plans, egress plans, fire service access plans

Section 2: Compartmentation

Purpose

Fire compartmentation divides a building into distinct zones that contain fire and smoke for a defined period, allowing occupants to evacuate, limiting property damage, and providing safe zones for defend-in-place strategies.

Compartment Sizing

IBC (US):

• No explicit maximum compartment size for most occupancies (controlled by

construction type and area per floor)

• I-2 smoke compartments: max 2090 m² (22,500 ft²) per smoke compartment

per IBC 407.5.1

• I-3 smoke compartments: max 2090 m² (22,500 ft²) per IBC 408.6

BS 9999 (UK): Maximum compartment sizes by risk profile:

Approved Document B (England & Wales): Maximum compartment sizes by purpose group:

(*Flats: each dwelling is a compartment; common corridor/stair protected)

Fire-Rated Construction Types

Fire Barrier (IBC 707):

• Continuous from floor slab to underside of floor or roof slab above

(deck, not ceiling)

• Used for: occupancy separation, exit enclosures, shaft enclosures,

horizontal exits

• Supports: must be supported by construction with equal or greater FRR
• Continuity: all joints, penetrations, and openings must be protected

Fire Partition (IBC 708):

• May terminate at underside of a fire-rated floor/ceiling or roof/ceiling

assembly

• Used for: dwelling unit separation, sleeping unit separation, corridor walls
• Less stringent than fire barrier (can stop at ceiling if ceiling is rated)

Fire Wall (IBC 706):

• Structurally independent (remains standing if structure on either side

collapses)

• Extends from foundation to roof (through roof unless roof is fire-rated)
• Creates separate buildings for code purposes
• Rating: 2 hr (A, B, E, F-2, M, R, S-2, U), 3 hr (F-1, H-3/4/5, S-1),

4 hr (H-1, H-2)

Smoke Barrier (IBC 709):

• Continuous membrane from floor to floor, outside wall to outside wall
• Smoke-tight construction with smoke dampers at duct penetrations
• 1-hour minimum fire resistance
• Used for: I-2 smoke compartments, I-3 smoke compartments, ambulatory

care smoke compartments

Fire Door Ratings

IBC/UL system (US):

British Standard / European system:

Fire Door Furniture and Ironmongery

• Self-closing device: overhead closer (EN 1154 / UL 228) mandatory on

all fire doors; min closing force per accessibility requirements

• Intumescent strips: 10 mm x 4 mm or 15 mm x 4 mm strips in rebate or

door edge; expand at 150-200°C to seal gap between door and frame

• Smoke seals (cold smoke): flexible blade or brush seal at head and jambs;

required for FD__S designations and IBC smoke doors

• Hinges: steel butt hinges, minimum 3 per door leaf; no rising butts on

fire doors

• Locks and latches: must not compromise fire rating; typically tested as

part of fire door assembly

• Hold-open devices: electromagnetic hold-open connected to fire alarm;

releases on alarm or power failure; door closer then closes door

• Panic hardware: fire-rated panic bar or touchpad (IBC requires on assembly

and educational exit doors for occupant loads > 50)

Glazed Fire Barriers

Types of fire-rated glass:

• Integrity-only glass prevents flame and hot gas passage but radiates heat.

Maximum area limited to prevent radiant heat exposure on escape routes.

• Insulating glass (intumescent gel between layers) blocks both flame and

radiant heat. Can be used for full fire barriers including in escape routes.

Firestopping (Penetration Seals)

Every penetration through a fire-rated assembly must be sealed with a listed firestop system:

• Pipe penetrations: intumescent pipe collars (combustible pipes --

PVC, PE, PP); mineral wool + intumescent sealant (metal pipes with insulation)

• Cable penetrations: intumescent block, putty, or pillows; cable

transit frames for large cable bundles

• Duct penetrations: fire damper (integrity only) or fire/smoke damper

(integrity + smoke sealing); rated to match wall rating

• Structural joints: fire-rated joint sealant (silicone or intumescent)

with mineral wool backing

Cavity barriers:

• Required in concealed spaces (above ceilings, within walls) to prevent

unseen fire spread

• Maximum distance between cavity barriers: 20 m in any direction (ADB);

IBC Section 718 requires draft stopping in floor/ceiling spaces of combustible construction at max 280 m² (3,000 ft²)

• At compartment wall/floor junctions extending into concealed spaces

Section 3: Means of Egress Design

Number of Escape Stairs

IBC (US):

• Based on occupancy, travel distance, and floor area
• Minimum 2 exits from each floor (with single-exit exceptions per

Table 1006.2.1 for small, low-hazard spaces)

• 3 exits for 501-1,000 occupants per floor; 4 exits for > 1,000

BS 9999 / Approved Document B (UK):

• Single stair permitted for buildings up to 11 m (ADB) in certain

occupancies with limited floor area and travel distance

• Number of stairs based on maximum travel distance from any point to

nearest stair AND stair capacity calculation

Travel Distances -- International Comparison

IBC (US), sprinklered:

BS 9999 (UK), Risk Profile B1 (office, normal risk):

Approved Document B (England & Wales):