Fire Ratings


Understanding Door & Frame Fire Ratings

Fire rated door tags

The purpose of a fire-rated door is to hold back smoke and contain fire long enough for the occupants of a structure to escape. The term fire rated means that the door, when installed properly, is not supposed to combust during a certain time period in the average fire. Fire rated doors are heavier than Residential doors, often made from durable, fire resistant materials like metal or mineral core.

Standard time ratings will vary from 20 min. – 180 min. according to the occupancy of the area in which the door is located. Depending upon area, small companies or government agencies may determine fire ratings.

Certain buildings or remodeling jobs often require a fire rated door. Installations like public buildings, office buildings, in living spaces like dormitories and in exit stairwells regularly call for fire rated doors.

A few things that renders a fire door ineffective is improper installation, propping it open or non UL listed hardware. If the door is not shut, it can’t hold back smoke or contain fire. As a result, plans may call for an automatic shut mode if fire is detected. Other doors are required by law to be self-closing with a latching lock so that they will be kept shut at all times, except in an emergency exit.

Our doors sold at B&M are fired rated, but some have a window, or Vision kit, which reduces the fire rating. In order for the door to keep a specific fire rating, the size (in square inches) of the visible glass is restricted.

Often, the doors are installed in rated walls, which have been tested for their ability to contain fire within a certain time period. Each fire rated door must be installed with UL rated hardware and sealants to maintain the fire rating.

Usually, contractors skilled in this area perform the installation. When installing fire rated doors, lives may depend upon the installer’s ability to adhere to all specifications required to maintain the fire rating.  For this reason, many clients have the professionals at B&M install fire rated doors for them.

B&M Fire Rated Frames

  • Our stock masonry HM frames have an embossed fire label and are 3 hour rated.
  • Our stock drywall HM frames have an embossed fire label and are 90 minute rated.
  • Our flush face HM frames have an embossed fire label and are 90 minute rated.

B&M Fire Rated Doors

Door openings are classified by their location in the building as designated by National Board of Fire Underwriters. Our stock 12×12, 7×22, 6x27and 5×35 bronze vision kits w/wire or laminate glass are allowed under Classification B, 90min fire rating with a maximum of 100 sq. in. visible glass per door leaf. This vision kit changes the flush face door rating from 3hr. down to 90min. Also if the building wall is only 1hr fire rated then even if the door does not have a vision kit it will only be rated the same as the wall ( the lowest fire rated component ).
Our stock solid wood door slabs are neutral pressure and are for interior use only, they are rotary cut natural birch constructed for either 20 or 90min fire ratings ,meeting WDMA & AWI quality standards. CLICK HERE for a complete list of Door Opening Ratings.

Our Stock 20 min solid wood doors are constructed with bonded 5 ply hot press, with a bonded particleboard core (conforming to ANSI A 208.1 1 LD-2). All veneer species are medium density overlay (MDO) for door gaces with crossbands made of high fensity fiberboard (HDF) utilizing Type 1 waterproof adhesives. They are prefit for various door openings and Beveled on the lock side only.

Our stock 90 min construction doors are constructed with bonded 5 ply hot press with fire approved hardwood edges. The solid core utilizes asbestos-free incombustible mineral, which can have labeled fire ratings up to 90 min. All veneer species are medium density overlay (MDO) for door faces with crossbands made of high density fiberboard (HDF) utilizing type 1 waterproof adhesives. They are prefit and beveled on the lock side only.

Other specis of wood doors (red oak, etc…) also keep fire ratings and are available upon request.  We are licensed to machine the hinge and lock locations as required which does not affect the fire rating of the door. Vision kits can also be installed ( see Door Opening Ratings). While our stock louvers are not fire rated, fire rated louvers can be ordered as needed.

All Stock HM flush face doors without panels, vision kits or louvers have a Mylar fire label and are rated 20min – 3hr.

Door openings are classified by their location in the building as designated by National Board of Fire Underwriters. Our stock 12×12, 7×22, 6x27and 5×35 bronze vision kits w/wire or laminate glass are allowed under Classification B, 90min fire rating with a maximum of 100 sq. in. visible glass per door leaf. These vision kits change the flush face door rating from 3hr. down to 90min. Also if the building wall is only 1hr fire rated then even if the door does not have a vision kit it will only be rated the same as the wall ( the lowest fire rated component ).

Be aware that the Door Opening Ratings is a guide.

Only when approved by the Authority having jurisdiction ( State Fire Marshal ) fire rated glass such as FireLite® may be used to keep certain fire ratings.

Transoms, Sidelites and Borrowed Lites

Transoms, Sidelites and Borrowed Lites are all constructed from hollow metal (HM) 16 gauge masonry stick frame and mullion material. To keep a fire rating, all corners are required to be welded on the face and well as the mullion faces so nothing is removable.

Have questions about fire ratings for your project? Contact us today!