Building Safety Systems: Fire Barriers, Electrical Wiring, and Code Compliance
Fire Barrier Protection Systems and Components
A fire barrier protection system helps contain fire and smoke to one location by preventing its spread from barrier to barrier. Various systems, including fire and smoke dampers, fire doors, and firestopping, help minimize property damage.
Key Barrier Management Components
Fire walls, fire partitions, and smoke barriers are crucial parts of a building’s barrier management system. Firestopping involves the maintenance of holes and gaps where items penetrate these systems.
Types of Walls in Fire Safety
- Fire Walls: Designed to prevent the spread of fire within a structure.
- Party Walls: Located on a lot line between two buildings.
- Fire Partitions and Fire Barriers: Vertical elements with specific fire-resistance ratings.
- Enclosure and Shaft Walls.
- Curtain Walls: Non-load-bearing exterior walls attached to the outside of a building.
Specific Wall Definitions
- Fire Partitions: Walls that may not extend continuously through a building, erected from a floor to the underside of the floor above or to the bottom of a fire-rated floor/ceiling assembly.
- Fire Barriers: Walls that are required to terminate at the floor or roof deck. Fire-resistance rated walls must be continued and extended vertically from the top of the floor assembly to the bottom of the floor/ceiling assembly.
Dampers and Fire Doors
Fire and Smoke Dampers are required when HVAC systems penetrate fire walls that have a fire-resistance rating of 2 hours or more. A damper is a device used to restrict the passage of flames in duct systems.
Fire-Rated Assemblies and Characteristics
Fire partitions and fire barriers are vertical building elements, including walls and shaft enclosures, that have specific fire-resistance ratings. The number of openings is limited, and all openings and penetrations must also be rated.
Types of Fire-Rated Assemblies
- Fire Partitions
- Fire Barriers
- Horizontal Assemblies
Horizontal Assemblies are floor or ceiling, or ceiling or roof assemblies that have a fire-resistance rating. Walls, floor, and ceiling assemblies surrounding an area having the same fire-resistance rating create complete compartmentation or enclosure.
Fire Partition Characteristics
- Rating of at least 1 hour.
- Automatic sprinkler system required for lower ratings.
- Openings must be protected.
- The number of openings is not limited.
Fire Door Requirements and Ratings
NFPA 80: Standard for Fire Doors and Other Opening Protectives governs the installation and maintenance of fire doors.
The International Building Code (IBC) and International Residential Code (IRC) require that doors and frames be given a fire-resistance rating after extensive testing by an approved agency. Once tested, the door and frame receive a label describing the duration of protection expected when exposed to fire.
When combined, all components form a protective assembly. Therefore, all components—including the door panel, doorframe, locksets, gaskets, hinges, and door protection plates—must include a rating label.
Fire Door Ratings and Types
Fire-rated doors and frames vary from 20 minutes to 3 hours, representing the duration of fire protection. Only steel doors and frames typically earn a three-hour rating.
Types of doors include:
- Swinging
- Sliding
- Folding
- Vertical
- Revolving
Testing Standards for Fire Safety
The following standards ensure assemblies resist fuel loading through heat transfer:
- ASTM E119 (Standard Test Methods for Fire Tests of Building Construction and Materials)
- UL 263 (Standard for Fire Tests of Building Construction and Materials)
- NFPA 221 (Standard for High Challenge Fire Walls, Fire Walls, and Fire Barrier Walls)
Note: ASTM E-119 (UL 263) are the testing standards for walls.
Electrical and Telecommunications Systems Design
The lighting and electrical design is typically divided into the following parts:
- Electrical Design
- Lighting Design
- Fire Alarm Design
- Telecom Design
Understanding Electrical Outlets and Voltage
Different appliances require different voltage and amperage ratings:
- 110 Volt 15 Amp: Suitable for the majority of electronic needs, such as TVs, microwaves, and small air conditioners.
- 110 Volt 20 Amp: A horizontal pin is an obvious indicator that this type of outlet is required.
- 220 Volt 15 Amp: Used for more powerful appliances that increase the demand on the electrical system. Power is doubled, requiring larger plugs than normal 110 Volt plugs. Washers, dryers, and commercial-sized air conditioners commonly use this plug.
Junction Boxes and Wiring Protection
A Junction Box is a crucial part of electrical wiring systems for homes and buildings. These metal or plastic boxes house and safely protect a structure’s electrical connections.
Junction Box Sizes and Function
Electrical casings typically come in two sizes:
- Three-wire boxes measuring 2 inches by 3 inches with a depth of 2.5 inches.
- Boxes with five or more wires that measure 2 inches by 3 inches and have a depth of 3.5 inches.
The junction box serves as the communal meeting spot for electrical wires, where they connect before moving on. These boxes protect hot (black), neutral (white), and grounding (green or copper) electrical wires, and may contain other wire colors for secondary functions and lighting.
Telecommunications Outlets
A Telecommunications Outlet describes a connecting device in the work area where horizontal cable (a commercial cabling term) terminates. The outlet/connectors are held in place on a telecommunications outlet box.
A wide variety of outlets are available on the market, supporting various connectors and designed to suit the environment where they are installed. The outlets are available in different colors, designs, and configurations.
Interior Designer’s Role in Electrical Planning
Interior designers are responsible for showing electrical system information on their drawings. The electrical engineer uses the interior design drawings to help design the electrical system. These drawings often indicate all electrical outlets, switches, and lighting fixtures and their type.
Large equipment and appliances should be indicated, along with their electrical requirements. Communication system equipment, like public phones, phone outlets, related equipment, and computer outlets, must also be shown.
In new buildings, the location and size of equipment rooms, including switching rooms and electrical closets, should be coordinated with the electrical engineer. The designer should be familiar with the location and size of the electrical panels and with the building systems that affect the type of wiring used, such as plenum mechanical systems.
The interior designer must know the locations of existing or planned receptacles, switches, dedicated outlets, and ground fault circuit interrupters (GFCIs). Lighting fixtures, appliances, equipment, and emergency electrical systems affect the interior design. Coordination of equipment room locations and knowledge of an uninterrupted power supply or standby power supply are also important.
Electrical Codes and Safety Standards
The National Electrical Code (NEC), also known as NFPA 70, sets the minimum standard for all electrical design for construction and is revised every three years. It is the only model electrical code published and is the basis for electrical codes in almost all jurisdictions.
While interior designers rarely use the NEC directly (as it is the responsibility of the electrical engineer or licensed electrical contractor), they must know basic code requirements since they typically specify the location of electrical outlets and fixtures. The electrical code includes restrictions on the proximity of electrical components and plumbing, for example.
Key Standards Organizations
Standards for electrical and communications systems are set by:
- American National Standards Institute (ANSI)
- National Electrical Manufacturers Association (NEMA)
- Underwriters Laboratories (UL)
In addition, the Americans with Disabilities Act (ADA) specifies mounting heights for outlets and fixtures in handicapped accessible spaces.
Grounding and GFCI Protection
Contemporary outlets include a half-round hole that receives the grounding plug. A contact leads from this hole to a green grounding screw that should be connected to the house ground (metal conduit or a green wire) to provide protection against shock when an appliance is plugged in.
A Standard/Conventional Duplex 15 amp 125-volt outlet powers anything from your toaster to a desk lamp.
Ground-Fault Circuit Interrupters (GFCIs)
Every year, hundreds of Americans die due to electrical accidents called electrocution—death caused by electric shock. Before the widespread adoption of GFCI outlets, around 800 people died annually in the United States.
Thanks largely to the proliferation of GFCI (Ground-Fault Circuit Interrupter) technologies, particularly in areas near water (such as bathroom sinks) or in places exposed to rain or standing water, that number has dropped significantly (to around 200 deaths per year). GFCIs provide critical protection against electrical shock.