Performance-based Approach + Fire Safety Designs

Alternative Fire Safety Solution with Life Safety Criteria,
Cost-effectiveness & Flexibility

Performance-based fire engineering, also known as performance-based fire safety design, is an alternative approach that applies both science and engineering to design effective fire protection systems for buildings and protect occupants, properties, and buildings. It combines fire engineering principles with calculations and software modelling tools to satisfy established fire code requirements, while also offering added flexibility to achieve a desired level of safety.

Find out more >> SCDF Fire Code 2018

Most governing bodies feature generic ‘checklist’ requirements through prescriptive building and fire codes, which may not fully capture the unique safety requirements that a building has. Performance-based fire engineering overcomes this issue by directly assessing the built environment, analysing risks and opportunities, and conducting engineering calculations to ultimately formulate an individualised and unique fire safety design for clients.

Some elements that performance-based fire engineering considers include the structure of a built environment, the availability and locations of fire exits, construction materials utilised, as well as the activities being conducted in the environment. This allows us to design several candidate designs for clients to choose from, which can include different variations on layouts and safety systems.

Through performance-based fire engineering, SHEVS IFT is able to continually deliver tailor-made fire safety designs that are resilient yet cost effective, while delivering comprehensive fire safety that adheres to existing fire codes and safety regulations.

In general, the key stakeholders involved in the performance-based plan submission process include:

Building Owner / Developer
Qualified Persons (QP)
Peer Reviewer (PR)

Registered Inspector (RI)
Authority Having Jurisdiction / Singapore Civil Defence Force (SCDF)

Find out more >> SCDF Singapore Fire Safety Engineering Guidelines (SFEG 2015)

Common deviations and non-compliances:

Extended smoke reservoir size and length
Mechanical replacement supply air for smoke control system
Enlarged fire compartmentation (vertical and horizontal)
Inadequate egress capacity e.g. shortfall of exit staircases
Extended 2-way travel escape distances
Extended discharge distance from exit staircases to external
Excessive unprotected openings e.g. setback distance of building from boundary
No fire separation between driveways and production/storage areas.
No fire separation between stage and seating for theatres.
Extended floor area of rooms discharging smoke into the atrium spaces.
Inadequate remoteness of exit staircases

Mitigating Fire Safety Measures

SHEVS (Smoke and Heat Exhaust Ventilation System) – natural or mechanical smoke control system to maintain safe and tenable escape paths for occupants.
Fire detection – aspirating, smoke, heat or flame detection system for early warning to occupants to commence evacuation.
Fire suppression systems – sprinklers, deluge systems, water monitoring system etc to mitigate fire sizes.
Escape facilities – emergency exits, fire lifts, evacuation lifts, exit staircases etc to facilitate occupant evacuation.
Building design, fire compartmentation and space planning – Occupancy load, travel distances, fire compartment size etc.
Fire and smoke modelling to assess tenability limits i.e. ASET (Available Safe Escape Time).

SetBack Distances from Notional Boundary

Due to the site constraints, the erection of a new hangar linked to its existing hangars had posed challenges for compliance to maintain minimum set back distances from its adjacent buildings. Minimum setback distances are required to ensure no lateral fire spread from one building to the other.

With appropriate fire suppression system, strategic fire compartmentation and fire safety engineering methodologies, the inadequate setback distance of the new hangar can still satisfy the acceptance criteria in terms of radiation assessment.

For a more robust and sustainable design that will not be affected by neighboring building modifications, the acceptance criteria for radiation heat flux assessment at the notional boundary line shall be adopted.

Enlarged Smoke Reservoir Size and Length

For a prescriptive natural engineered smoke control design, the maximum smoke reservoir size and length are limited to 2,000m² and 60m respectively i.e. multiple smoke zones are required for larger spaces.

Performance-based design for a single smoke zone without smoke barriers can be applied with CFD Modelling for smoke assessment and Evacuation Modelling for movement time to determine the ASET/RSET factor.

Cost-effectiveness in construction costs and full flexibility in warehouse tenancy layout can be achieved based on a single smoke zone performance-based design.

Enlarged Smoke Reservoir Size and Length

Extended Travel Distances and Excessive Occupant Loads

An elevated field of Eunoia Junior College would require at least 20 exit staircases for an occupant load of 5,000 pax. A performance-based approach with less than 50% exit capacities were provided for to address the increased occupant load.

With early involvement of SHEVS to develop an effective fire safety design with appropriate fire safety engineering methodologies, performance-based design objectives can still be achieved at an acceptable level of life safety.

With appropriate mitigating fire safety measures to prevent congestion and bottle-necks at the exit provisions, optimal exit provisions can be concluded to achieve an acceptable level of life safety criteria.

Extended Fire Compartmentation by height for Atrium

In lieu of fire compartmentation by height and size for atrium space of a 4-storey shopping mall, CFD modelling for a shop fire at the lowest floor was conducted to assess the effectiveness of the engineered smoke control system in the atrium space.

CFD results have demonstrated that tenability limits were maintained at all floors for the safe evacuation of the occupants.

Holistic approach to assess the effects of smoke and fire is important to formulate a cost-effective and well-balanced fire engineering solution. For a sprinklered building, in lieu of a fire compartmented room, the smoke plume out of the room of fire origin into atrium spaces for smoke extraction can be an effective and well-balanced alternative solution to address the smoke conditions as well as fire spread.

CFD Model of an Extended Fire Compartmentation

Performance-based Approach + Fire Safety Designs

Projects