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Lesson 5 | Doors

Slide 1 of 15

Thank you, Mark. Firefighters must force entry into the fireground as part of their duties. It is impossible to extinguish fires or start searches until firefighters enter. In addition to breaking through the doors, windows, walls, and floors, you must also gain access to the security devices used to prevent unauthorized entry. A door’s construction material affects its fire barrier performance and ability to be forced open during an emergency. Let’s look at the types and construction materials of doors that affect how well they function as fire barriers and how easily they can be forced open during an emergency.

So, let’s get started!

Slide 2 of 15

The operation, style, design, and construction of doors vary greatly. How they operate is a general way to classify them. Doors commonly used in modern construction include swinging, sliding, folding, overhead, and revolving doors. Here’s a brief note on each type:

• A swinging door rotates on pivot posts supported at the top and bottom or on hinges attached to the side jambs of the doorway. They are usually required as exit doors as a means of egress.
• An overhead track suspends a sliding door, which uses steel or nylon rollers. They never serve as a means of egress since they impede people’s movement.
• Similar to sliding doors, folding doors are hung from an overhead track with rollers or glides. As a means of egress, horizontal fire door assemblies must meet specific requirements and be tested.
• The overhead door is a door that opens in a vertical plane. It is possible to lift a vertical door manually, mechanically by a chain hoist, or through power.

There are three or four sections or wings on a revolving door that rotate in a circular pattern. People fleeing an emergency have difficulty moving quickly through revolving doors in a fire situation. The revolving door’s wings collapse under pressure to overcome these restrictions and provide an unobstructed opening.

Slide 3 of 15

Additionally, you may encounter glass or metal doors while performing your duties.

• The use of glass doors is common both on the exterior and inside of buildings. They can be either framed or frameless. According to building codes, glass doors must be made of tempered glass that is resistant to breaking.
• Corrugated steel can be used in the construction of metal doors. The hollow steel or aluminum door is a common type of metal door.

Slide 4 of 15

Wood, metal, and glass are the most common materials used for doors. In addition to a panel or flush designs, wood doors may also contain glass components. In addition to aluminum and carbon steel, stainless steel, bronze, and copper are also commonly used. Furthermore, doors are sometimes manufactured with hardboard, fiberglass, or plastic veneers.

Slide 5 of 15

Fire doors are the most common way to protect openings through fire-rated walls. When properly maintained and operated, fire doors can limit total fire damage as well as other passive fire protection measures. Unlike ordinary or non-fire doors, fire doors differ in their construction, hardware, and the extent to which they must close automatically. It is essential to take note of fire doors during pre-incident surveys since they may be installed in unexpected locations.

It is common for fire doors to be constructed on metal and to roll, slide, or swing into place when released.

Slide 6 of 15

In a similar way to fire-resistant structural assemblies, fire doors are rated for their fire resistance. A fire door’s time rating ranges from 20 minutes to 4 hours. The half-hour and one-third-hour doors are primarily used in smoke barriers and openings to corridors.

A fire door may also be classified according to its time rating and a letter indicating the type of opening. In a previous system, letters were historically used to specify the type of opening or the door itself. In older buildings, letter designations may still be found. Following is a list of letter designations:

• Class A – Openings in firewalls
• Class B – Openings in vertical shafts and openings in 2-hour rated partitions
• Class C – Openings between rooms and corridors having a fire resistance of 1-hour or less
• Class D – Openings in exterior walls subject to severe fire exposure from the outside of a building
• Class E – Openings in exterior walls subject to moderate or light exposure from the outside

Slide 7 of 15

The entire rated fire door assembly must have the same degree of fire resistance as fire-rated walls, to ensure that a fire can’t spread. When a fire develops, light-weight panel doors or glass doors cannot protect themselves from the high temperatures. Further, fire resistance is affected by the material used in construction.

Listed below are the requirements for fire doors:

• NFPA 1, Uniform Fire Code
• NFPA 80, Standard for Fire Doors and Other Opening Protectives
• NFPA 101, Life Safety Code
• NFPA 5000, Building Construction and Safety Code

Fire doors are designed for use in specific types of settings. The four styles of fire doors identified in NFPA 80 are described in the following slides.

Slide 8 of 15

Overhead rolling fire doors are commonly used to protect fire wall openings in industrial buildings and fire areas separated by walls. It may be placed on one side or both of a wall opening or doorway. In addition to being relatively inconspicuous, these doors do not take up any additional wall space. A roll-up (overhead) door usually closes under gravity when a fusible link melts, or a smoke detector releases its hold-open mechanism. Alternatively, there are motor-driven doors.

It is never recommended to use rolling doors in paths of egress. A dead-end corridor may be created if no egress is available when the overhead door closes. Additionally, doors that close after firefighters pass through them can pose the following risks:

• Disorient firefighters who do not realize that the door closed the corridor behind them
• Trap firefighters in the fire area
• Cut off firefighter’s escape path
• Restrict water through pinched hose lines

In heavy smoke, firefighters may be unable to see the tracks of overhead doors on each side of a door opening. It is essential that firefighters take precautions in case the door suddenly closes.

Slide 9 of 15

Old industrial buildings often have horizontal sliding fire doors. Fusible links usually hold these doors open. By either gravity or a counterweight, the door slides along a track when the link is activated. For openings in walls that are required for egress, horizontal sliding doors cannot be installed.

In general, horizontal sliding doors are metal-clad or tin-clad doors with a wood core that provides insulation and are covered in sheet metal that protects the wood. When wood is exposed to heat, it undergoes thermal decomposition, so a hole in the sheet metal is usually used to vent the gases produced during the process. Terneplate, steel, and galvanized sheet metal are commonly used in the manufacture of horizontal sliding doors.

Slide 10 of 15

A swinging fire door is usually used to protect stairwell enclosures and corridors. Various swinging fire doors are available, ranging from 20 minutes to 3 hours. There are various materials to choose from when building swinging doors, including metal-clad wood. It is ideal in places where the door is frequently closed, and pedestrian traffic is present, although swinging fire doors require clear space around them to ensure closure. Two sets of doors and a vestibule may offer the necessary level of protection when a firewall needs to be penetrated.

Slide 11 of 15

The code identifies parameters for special-purpose fire doors that can be used in applications, including:

• Freight and passenger elevators
• Service counter openings
• Security (bullet-resisting)
• Dumbwaiters
• Chute openings

The horizontal sliding accordion or folding doors are other types of special-purpose fire doors. Both types of doors are motor driven and require electrical power for operation. An alarm system or smoke detector triggers the door to close. The motor is powered by a battery when the regular power supply is interrupted.

When a fire-rated partition is required, and the designer does not wish to provide a fixed wall, horizontal sliding accordion or folding doors can be used.

Slide 12 of 15

If a fire door is to block the spread of fire effectively, it must remain closed and attached to the fire wall at all times. A fire door’s hardware must be designed to securely latch the door closed in the event of a fire. Also, if a fire door is installed in a frame, the frame must also withstand fire damage. The testing of fire doors includes the frames as well as the hardware.

Slide 13 of 15

The fire door must be closed during a fire to prevent the spread of fire. A fire door must, however, remain open and/or usable during non-fire conditions. The following tools and combinations of tools preserve a door’s function both as a fire barrier and portal through a partition:

• Various fire doors can be held open with a hold-open device, including swinging, sliding, and rolling doors. A fire door holder is helpful in school stair enclosures, where there is a large volume of traffic.
• Sliding and swinging fire doors can use door closers. When a door hold-open device is used, the door will automatically close when it is signaled. The devices that react to smoke or temperature quickly respond and can be easily reprogrammed. Fusible link closers are generally used on doors that close only during a fire.
• A door operator opens and closes a door for normal use. They are often used with sliding fire doors mounted on a level or inclined track. In the event of a fire, a fusible link disconnects the operator and allows the door to close using either a spring-powered door closer or a suspended weight system.

Slide 14 of 15

It is imperative that the doors protecting the openings operate correctly and close under fire conditions in order to achieve compartmentation effectiveness. Proper maintenance is essential for proper fire door operation. When fire conditions are present, fire doors commonly fail to close properly. Damage to the following components will lead to a door failure:

• The door closer
• The door itself
• Door guides

Slide 15 of 15

Fire doors are tested in accordance with the procedures contained in NFPA 252, Standard Methods of Fire Tests of Door Assemblies; also designated A-S-T-M E-152. The test procedure uses a furnace to expose the fire doors to the same time-and-temperature curve used to establish the fire-resistance rating of structural assemblies. Fire doors that pass a testing process are marked with a label or plate on the top or on the hinge side of the door that indicates information, including:

• Door type
• Hourly rating
• Identifying the symbol of the testing laboratory

Although the door’s rating information can help building and fire inspectors while determining the opening’s protection, the information cannot protect against limitations, including:

• An assembly of rated doors and frames does not necessarily indicate a rated wall.
• The appearance of a lower fire rating can be caused by damage to the labels, removal of labels, or concealment of labels.
• False information is given by counterfeit laboratory labels.

With this, we come to the end of this lesson and in the next one, Mark will take you through the final lesson on this topic, windows.

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