Fire vs Smoke vs Non-Combustible Doors
Pair fire-safety door in a Healthcare facility.
Requirements for fire protection in this facility were defined by building class and doorset positioning in compartmentalising rooms.
There are many construction standards and compliance measures to consider when specifying doorsets for a commercial building. Door safety requirements vary depending on the likes of building class, building traffic/density, and present risks. Custom configurations of safety doors are designed to meet each of these requirements; varying in their protection against heat, fire, and smoke. For each of these purposes are Fire Doors, Smoke Doors, and Non-Combustible Doors.
What is a Fire Door?
‘Fire door’ refers to a complete doorset - door leaf, frame, and seals - as a component of the surrounding wall. Altogether, the doorset fills the wall opening with the purpose of resisting the passage of fire for a set period of time. The wall itself is considered in tandem as the wall and doorset together form a barrier compartmentalising one area/room to the next. This time gives occupants a period to safely evacuate the building. The requirements of a Fire Door involve six key considerations:
- Suitable door leaf materials. Among other components, it must feature a proprietary core built to withstand burning.
- A seal system. These seals eliminate any gaps where fire can pass through including around, under, and between doors.
- A materially solid frame. This can be composed of backfilled metal or of timber but must always be solid throughout to form an appropriate barrier.
- Compliance testing and certification. All components of the doorsets have been tested together according to AS 1530.4:2014 by an independent NATA accredited organisation. As a result, the doorset is given a fire resistance level defining the time period that it is proven to be a fire-resistant barrier (typically 1 or 2 hours).
- Correct installation. Even if a fire door’s build is proven as compliant, it is still subject to correct installation in order to fulfil its purpose. According to AS1905.1:2015 this includes the assurance that clearances around the door are not exceeded (3mm max at its top and sides, and 10mm max at its bottom). Installation must also clearly signify its fire-protection with a front-of-door sign as well as clearly displayed fire tags fixed to the frame (both pictured).
- Essential maintenance. A fire-rating is provided conditionally, the doorset’s fire-protection function must be re-confirmed over time with regular inspections.
What is a Smoke Door?
A smoke door is a doorset with the purpose of blocking the transfer of smoke from one side of the door to the other. Preventing this requires the appropriate sealing of the doorset in much the same way as a fire door. That is, the gap’s present between the door leaf and frame, as well as the door’s underside and the floor covering must be sealed. Pair/Double doors also require an additional seal (Meeting Stiles) along the doors’ leading edges to cover the between-door gap. The airborne passage of smoke is thereby obstructed and will not pass through for a set period of time. The seals used for this must be tested and approved as smoke-rated systems.
As fire and smoke go hand-in-hand, it is common for Smoke Doors to also be Fire Doors as the two are not mutually exclusive. It is not a requirement however; a door may be only smoke-rated if the door’s placement only deems this level of protection. The key difference is that the door leaf itself is not fire-rated as it is not fitted with a proprietary internal core. Rather, smoke sealing systems are typically approved for Solid Core doors as the solidity this provides, in conjunction with the seals, is enough to prevent smoke leakage.
What is a Non-Combustible Door?
Extreme heat can cause the door leaf to combust or ignite in flames. This is a result of the door leaf’s material taking on the heat from the air to a point that it catches fire. This begins with the door skins as the outermost layers which have the greatest exposure to the surrounding environment. As such, making the door non-combustible means fitting a Metal Cladding as metals are resistant to absorbing heat and catching fire in the way that standard doors skins like MDF, Ply, and Hardboard are. This is for instances where a non-fire rated door is compliant however the particular installation setting presents combustibility risk and so best practice is to mitigate this risk. One such example is electrical cupboards as the services present a natural combustion risk but the doorset typically does not require a fire rating to meet compliance requirements.
Varying Levels of Occupant Safety
Compartmentalising spaces from one another requires a Fire-Rated Doorset - often simply referred to as a Fire Door. This measurably slows the passage of fire, but can also be fitted with appropriate seals to double as a prevention of smoke passage too. Comparatively, a non-combustible door is a step down in fire protection as it is not rated to separate spaces from fire passage, but rather to mitigate risk of the doorset catching fire. Such doors are more a matter of building safety best practice than they Australian Standard compliance measures.
For further insight into specifying safety doors, get in touch with the Spence team.