Types of Fire-Rated Hollow Metal Doors for Enhanced Safety and Durability
Hollow metal doors
Fire-rated door assemblies play an important role in saving lives and minimizing property damage by providing safe egress and compartmentalizing smoke, flames, and when required, dangerous radiant heat. This combines the door, frame, hardware, and glazing as one assembly. These components are normally tested as separate products by a nationally recognized testing agency and then listed, labeled, or classified for use in fire door assemblies. However, there are instances where specific components are tested together and therefore must be used together to maintain the fire rating.
Fire door assemblies are tested to NFPA 252, Standard Methods of Fire Tests of Door Assemblies or UL 10 B, Standard for Fire Tests of Door Assemblies, or UL 10 C, Standard for Positive Pressure Fire Tests of Door Assemblies. Like fire window assemblies, fire door assembly testing includes fire endurance and hose stream tests. Note that building codes throughout the US typically stipulate that 20-minute doors are exempt from the hose stream test.
Fire-rated doors are tested following the following standards as per NFPA 252:
- UL 10B, Fire Tests of Door Assemblies (neutral or negative pressure)
- UL 10C, Positive Fire Pressure Tests of Door Assemblies
Honeycomb Door
The door can bear Up to 1 1/2 hours.
The door shall be a minimum of 44 mm thick.
As door infill, the rigid honeycomb structure is integrated with the door to form hundreds of small I- beams with the door, with a uniform thickness and flat surface that makes it possible to add lites, louvers, or other features as Optional. It reinforces the full width and height of the door. Honeycomb Core Doors can be used in exterior or interior applications. A door with a fire-resistance rating (sometimes referred to as a fire protection rating for closures) is used as part of a passive fire protection system to reduce the spread of fire and smoke between separate compartments of a structure and to enable safe egress from a building or structure.
Rockwool Door
The door can bear Up to 3 Hours.
The door shall be a minimum of 44 mm thick.
As door core, Rockwool is used to fill in cavities of steel-stiffened doors. Steel Stiffened doors are used mainly for exterior doors, where rigidity is important. They are available in varying degrees of strength and quality. While the thickness of the stiffeners can vary, the majority are made of 20-gauge steel. Heavier gauges sometimes are used, particularly on security doors. Spacing between stiffeners may vary. The Rockwool Core used for its fire doors has a high service temperature that can reach 780oC . Additionally, the core is water-repellent, non-hygroscopic, and non-capillary.
Fiberglass Door
The door can bear Up to 3 hours.
The door shall be a minimum of 44 mm thick.
Fiberglass is an extremely durable material that can maintain its shape for decades with little or no maintenance. This property makes them ideal for fire doors, as they will not warp or distort under extreme heat. In addition, materials are resistant to fire and smoke and will not contribute to the spread of flames. Fiberglass is non-conductive, meaning it will not conduct heat or electricity, making it an ideal material for use in electrical applications. Fiberglass are better material for fire doors because it can withstand higher temperatures without warping or melting.