By Jeffrey Stull
Perhaps the most recognizable piece of firefighting gear is the helmet. The distinctive shape of a classic fire helmet readily identifies firefighters when they're in public view. It is also a perfect example of both how modern technology has worked to provide improved protection and how resistant the fire service is to change.
In the past, helmets were made from leather (in fact, some still are). The vertical ribs along the sides of the leather helmet are actually reinforced seams, which protrude to permit the individual leather pieces to come together. In its time, this helmet was robust and protected firefighters from falling debris and elevated temperatures, which could be expected in higher portions of a room engulfed in flame and heat.
Obviously, there have been new designs that make use of high technology composite materials that are lighter and stronger. But even these modern helmets often take on the classic firefighter helmet shape.
Here are the main areas to remember when buying a new firefighter helmet.
The requirements for firefighter protective helmets are dictated by NFPA 1971 Standard on Protective Ensemble for Structural and Proximity Fire Fighting, which establishes a series of specific design and performance criteria. As personal protective equipment, helmets must be designed to meet a variety of protection needs: resistance to impact from falling objects, contact with electrical wire, high heat, and flame exposure, all while remaining light to prevent undue stress on the firefighter.
The required features of the helmet are: a shell, an energy absorbing system (for impact), a retention system (controlling how the helmet fits to the firefighter’s head), retro-reflective/fluorescent trim, ear covers and either a faceshield or goggles (or both). Today's helmet shells are made of thermoset resin composites or thermoplastics. Thermoset resin composites are special high temperature resins to bind the glass and Kevlar or other fibers together. Thermoplastic helmet shells provide greater impact and penetration resistance compared to fiberglass, and they will hold up through repeated thermal exposures. In contrast, fiberglass helmet shells can better resist chemical exposure and tend to be more stable at high temperatures.
Different approaches are used for absorbing energy. Some manufacturers use foam inside the helmet in combination with the helmet’s suspension (the straps forming the head cradle inside the helmet). Other manufacturers have been able to provide sufficient energy absorption through the suspension system alone. The helmet suspension consists of a headband that fits into the helmet shell through sockets, pins and other hardware in combination with webbing materials to fit the wearer’s head. The headband must be adjustable through a ratchet or other means to fit the firefighter's head and interface correctly with the SCBA facepiece and protective hood. The headband can be lined with leather or other material for comfort.
The helmet is secured on the firefighter's head through a retention system that consists of a chin strap, webbing (generally Nomex) and sometimes a nape device that goes to the back of the head; both are attached to the helmet and provide adjustment through buckles, slide mechanisms, and hook and loop closure (Velcro). The trim placed on the outer shell offers enhanced visibility, which together with reflective trim on garments allows firefighters to be distinguished in poor visibility situations. Ear covers extend down from the helmet on the sides and back to provide additional thermal protection to the firefighter head and neck. The covers consist of similar materials to those used in the construction of firefighter garments. In the new 2007 edition of NFPA 1971, ear covers must consist of materials that provide a minimum thermal insulation with a thermal protective performance (TPP) rating of 20.0.
Goggles and Faceshields
Helmets are now required to be provided with goggles, faceshields or both; however, the latest edition of NFPA 1971 specifies that the goggle need not be affixed to the helmet. Many within the fire service have radically different opinions about the optimal means of eye/face protection.
Optional Characteristics and Features
In addition to the aforementioned helmet requirements, there are several optional characteristics and features. Many departments display a shield or heraldry signifying the department or the firefighters rank. Some manufacturers have created features that help protect the goggles (when worn on helmets) from dirt and heat to provide undistorted vision when clearly needed. There are also accessories for attaching thermal imaging cameras, lights, and other devices.
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Jeffrey O. Stull is a FireRescue1 columnist and president respectively of International Personnel Protection, Inc., which provides expertise on the design, evaluation, selection and use of personnel protective clothing, equipment and related products to end users and manufacturers. International Personnel Protection, Inc. has conducted numerous studies for effectiveness and performance of protective clothing and equipment. The original version of this article can be seen at Selection of Firefighter Protective Ensembles, Part 1.