Fire Safety During Fit-Out Works: Hot Work, Isolations and Escape

A floor is most exposed while it is being fitted out

Fire safety in a finished office rests on its systems: detection, alarm, sprinklers, compartments, escape routes. The common assumption is that those systems protect the floor during the works as well. Often they do not, at least not fully.

During a fit-out the risk peaks. Fuel is at its highest: cartons, plastic wrapping, timber offcuts, adhesives, paints and solvents on an open floor. Ignition sources multiply: welding and grinding, temporary electrics, extension leads, tools on charge. Protection is reduced: detector heads covered against dust, sprinkler sections drained while heads are moved, fire doors propped open for deliveries. And the people on the floor are workers who may not know the building's escape routes.

For a business the consequences go beyond the damage. A fire on a fit-out site can delay a move by months, complicate insurance claims, and in an occupied building put staff at risk. Even false alarms carry a cost, through evacuations of the whole building and lost goodwill with the landlord and other tenants.

Where the risk comes from, and how it is controlled

Construction safety, including fire safety on site, is addressed in NBC 2016, Part 7, which deals with construction management, practices and safety. The arrangements for a particular site are agreed by the contractor, building management and the project's safety and fire advisers.

Hot work permits

Hot work is any task that produces heat, sparks or flame. In an office fit-out that typically includes welding steel supports, cutting and grinding, brazing refrigerant pipes and torch-applied waterproofing on terraces and wet areas. Fire precautions for welding and cutting are set out in IS 3016.

A working permit system usually covers:

• The task and the place, stated precisely, with a start and end time.
• Preparation of the area: combustibles removed or covered with fire-resistant sheets, openings in floors and walls protected so sparks cannot travel.
• Detection in that zone, if it must be isolated, isolated only for the task and restored afterwards.
• Fire-fighting equipment at the work point.
• A fire watch during the work and for a period afterwards, set by the site's procedure, because smouldering material can ignite later.
• Sign-off on completion, confirming the area was checked before the permit closed.

The most effective control is to need less hot work. Mechanical and press-fit pipe joints, bolted connections, cold cutting and prefabrication away from the floor all reduce it, and scheduling unavoidable hot work before combustible finishes and furniture arrive reduces the fuel nearby.

Isolating detection and sprinklers without leaving the floor unprotected

Fit-out work regularly affects the base-building fire systems. Dust and fumes set off detectors, so heads are covered or zones are isolated. New ceilings and layouts mean sprinkler heads must move, so sections are drained. Neither is unusual. The danger lies in an isolation that is undocumented, wider than needed or never reversed. How these systems work is covered under fire detection and alarm and firefighting systems.

A sound isolation procedure answers these questions in writing:

• Who authorises an isolation, and who restores it.
• Which zone or section, as small as practicable, and for how long.
• What covers the gap: a fire watch, additional extinguishers, a stop on hot work in that area while it is unprotected.
• How it is recorded, in a log kept with building management.
• When it is restored: typically at the end of each shift, with detector covers removed and the zone checked.
• Who must be told: building management, the security desk, and anyone else the building's procedures or the insurance policy require.

Sprinkler heads also need protection while finishes go on; paint on a head can affect how it operates. Heads moved to suit the new layout should be coordinated with the ceiling design, and the system restored and checked before the area is closed up.

Storage, housekeeping and temporary electrics

Most site fires start small, in waste or stored materials, and grow because nothing stopped them. Daily discipline matters more than any single measure:

• Packaging off the floor every day. Cartons and plastic wrap are the largest single fuel source on a fit-out.
• Designated storage for materials, away from escape routes, exits, risers and electrical rooms.
• Flammable liquids kept to the quantity needed for the day, in closed containers, in a ventilated area.
• Temporary electrical distribution with appropriate protection, inspected regularly, with no daisy-chained extension leads, and switched off at the end of the day.
• Fire extinguishers selected for the hazards present, positioned near work fronts and exits, and kept accessible. Selection, installation and maintenance of first-aid extinguishers are covered by IS 2190.
• Fire-stopping as you go. Openings made in walls and slabs for services should be sealed as the work proceeds, not left until the end.

Escape routes in an occupied building

Where people continue to work in the building, or on the same floor, the escape routes that protect them must keep working throughout the fit-out. Hoarding, stored materials and temporary partitions must not block or lengthen a route without that being agreed. Fire doors must not be wedged open for convenience. Exit signs must remain visible, and the alarm must be audible inside the works area. Every worker should be inducted on the evacuation route and assembly point on their first day.

Fire and life safety provisions, including escape, sit in NBC 2016, Part 4. What is acceptable during works in a particular building must be agreed with the building's fire consultant, building management and, where relevant, the authority having jurisdiction. The phasing, dust and services side of working around staff is covered in fitting out an occupied office, and what a works policy typically covers in contractor's all risk insurance for fit-out.

Common mistakes

• Detector covers left on. Put on to stop false alarms and forgotten, they leave an area unprotected long after the works.
• Permits issued from the office. A permit signed without anyone looking at the work area protects nobody.
• Packaging left overnight. The largest fuel load on the floor sits next to the day's ignition sources.
• Isolating a whole floor for one room. Convenient, and far wider than the risk requires.
• Materials stored in stair lobbies or corridors. Out of the way of the works, and in the way of escape.
• No fire watch after hot work. Smouldering material ignites after the crew has left.

What to ask your contractor before work starts

• Who issues hot work permits, and who checks the area before and after?
• What is the isolation procedure for detection and sprinklers, and who signs it?
• Which zones will be isolated, for how long, and what covers the gap?
• Where will materials, flammable liquids and waste be stored?
• How are escape routes, fire doors and signage kept clear and checked?
• What fire-fighting equipment will be on the floor, and where?
• How are workers inducted on evacuation?

Standards referenced

Construction management, practices and safety in NBC 2016, Part 7; fire and life safety in NBC 2016, Part 4; fire precautions in welding and cutting in IS 3016; selection, installation and maintenance of first-aid fire extinguishers in IS 2190. The fire safety arrangements for works in a specific building, including isolations of fire systems and the maintenance of escape routes, must be agreed with the building's fire consultant, building management and the authority having jurisdiction.