FIRE DOOR RATINGS: ALL YOU NEED TO KNOW

In event of fire, fire-rated doors offer safe compartmentation of the building, prevent the spread of flames, smoke and hot gases, help to see whether anyone is trapped or unconscious behind a door, and enable occupants to see if escape routes are clear to permit safe and fast evacuation.

Fire-rated doors can be found in exit corridors, near stairwells and in elevator shafts to contain the spread of fire throughout a building; they must always be part of an assembly or system that includes frame, hardware and—for maximum visibility—glazing, ensuring that all components will work together as designed. Fire-ratings for fire-rated doors range from 20-90 minutes

When an assembly is referred to as fire-protective or fire-resistive, what’s being called out is the rating of the glass. Fire-rated doors, specifically, may be required to limit heat transfer from one side to another; such doors are called temperature rise doors. Vetrotech’s temperature-rise doors can be glazed with CONTRAFLAM intumescent glass products with a minute rating of 45 or higher. All temperature rise doors must past the hose stream requirement.

We always recommend checking the IBC and your local authorities having jurisdiction when it comes to fire-rated door requirements; our team can help you with that. The following are important standards for fire-rated doors:

• UL 10B, Fire Tests of Door Assemblies (neutral or negative pressure)
• UL 10C, Positive Fire Pressure Tests of Door Assemblies
• NFPA 252, Standard Methods of Fire Tests of Door Assemblies, and/or
• CAN4 S-104, Standard Method for Fire Tests of Door Assemblies

And these are other standards that may come into play:

• UL 1784, Standard for Air Leakage Tests of Door Assemblies and Other Opening Protectives
• ANSI Z97.1, Safety Glazing Materials Used in Buildings – Safety Performance Specifications and Methods of Test
• CPSC 16 CFR 1201, Safety Standard for Architectural Glazing Materials, for Category I or II as indicated in Table 2406.1.

Fire-rated doors are specifically tested for the following:

•  Meeting fire rating: This exposes the door to over 1,900 degrees F for the maximum fire-rating sought. A successful fire test will end with the door still in its frame with no openings and limited flames. Minute ratings are 20/45/60/90/180 minutes.
• Hose Stream: Immediately after the fire endurance test, the door will be blasted with a fire hose at 30 psi from 20 feet away. Doors that remain intact pass the hose stream test. (Note: 20 minute doors are not required to pass the hose stream.)
• Temperature Rise: This rating is in addition to a door’s minute rating. Here, the max temperature above ambient on the non-fire side is measured during the first 30 minutes of the fire endurance test. Ratings range from 250/450/650 degrees Fahrenheit, with the most stringent recognized as 250 degrees
• Smoke Control: 20 minute doors, while not required to pass the hose stream test, may be required to pass testing for smoke control as required in UL 1787.

One standard referenced above should be addressed in more detail: CPSC 16 CFR 1201, Safety Standard for Architectural Glazing Materials, for Category I or II. This outlines the impact safety rating required in glazing. Specifically, glass that meets this rating should either not shatter or break safely when hit by, for instance, a full-grown, fast moving adult.

When impact-resistant fire-rated doors are required, it is vital to make sure that the products meet CPSC 16 CFR 1201 Category I or II—but fire codes no longer allow fire-rated doors without an impact safety option. Building codes require that glazing used in hazardous locations, such as doors and sidelites, must meet minimum Category I and II impact standards, depending on the size of the glazing panel.

• Category I Impact test (150 lbs): Smaller glazing panels in sizes up to 1,296 square inches
• Category II Impact test (400 lbs): Larger glazing panels

Where are fire-rated doors required?

All fire-rated assemblies, including fire-rated doors, must meet all applicable code requirements, including the National Fire Protection Associated (NFPA), the International Building Code (IBC) and/or the International Fire Code (IFC).

In general, fire-protective fire-rated doors are permitted within fire partitions or corridor walls rated 30 minutes to 1 hour, and within 1-hour smoke barriers, per the IBC. Fire-resistive fire-rated doors are permitted in fire walls and fire barriers having a fire-resistance rating greater than or equal to 1 hour; enclosures for shafts, interior exit stairways and interior exit ramps; exterior walls with a required rating of 60-180 minutes.

See the chart below for more information about fire rating for doors in 1 hour wall and fire rating for doors in 2 hour wall.