All of the protective clothing and equipment worn by firefighters makes up an ensemble in which the items must work together to provide overall protection from fireground and other emergency hazards. A lot of focus has traditionally been placed on garment selection, but more and more attention is now being given to how all the parts of the ensemble - particularly helmets, gloves, footwear, and hoods - work together to provide the necessary level of protection.
In addition, firefighters are increasingly called on to perform a range of duties that includes more than just fighting structural fires. Firefighters are more likely to be involved in emergency medical care, technical rescue activities and other emergencies that do not involve the same set of hazards encountered in combating high heat and flames. Moreover, firefighters are generally the first responders for any kind of event, including terrorist actions that can include chemical or biological agents.
Despite these facts, few firefighters have the luxury of different clothing outfits for responding to varying types of emergencies, with the exception of those on specialized teams. Manufacturers have realized that in order for clothing to be versatile enough to adjust for changing missions, it must be lighter, more comfortable and, most importantly, work together with other parts of the ensemble to provide complete protection under changing circumstances.
This is first of a two-part article that addresses various ensemble elements. This first part addresses helmets and hoods, while the second will address gloves and footwear.
Helmets
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.
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.
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. The fact is that faceshields are not primary eye protection, as are goggles, and the faceshields provided on fire service helmets are significantly shorter than industrial faceshields designed for secondary eye protection. Nevertheless, the reliance on these items for any eye protection is sometimes questioned because when worn as part of the helmet, the ability for fire firefighters to clearly see through these items is affected by distortion caused by excessive heat exposure and soiling to which the items are constantly subjected when worn on the helmet.
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.
Hoods
Protective hoods have become an integral part of the firefighting ensemble. Minimum performance specifications for hoods exist in the NFPA 1971 standard. Intended as an interface item of protective clothing, separate hoods are typically constructed of knitted material with a face opening to fit around the breathing apparatus mask and "bib" extensions of the material to remain tucked under the firefighter's coat. In NFPA 1971, protective hoods have a lower thermal insulation requirement than garments (a TPP rating of 20, compared to the minimum 35 required for garments), but still have to meet all of the flame and heat resistance requirements typically associated with garment materials. As a consequence, protective hoods are heavy single ply or double ply materials using Nomex®, PBI®, P84®, Basofil®, Kevlar®, and FR rayon fibers.
Owing to their knit constructions, hoods are typically "one size fits all" but must be carefully selected to fit properly with the other equipment, primarily the SCBA facepiece. Because hoods are repeatedly stretched over the facepiece and the wearer's head, some hoods quickly lose their shape and can fail to properly protect the firefighter. NFPA 1971 has attempted to address this requirement with a test for measuring the hood face opening size after repeated donnings and doffings of the hood on a manikin headform.
Features for hoods are relatively simple. These usually consist of: the type of face opening (some hoods are designed to accommodate specific respirator facepieces); the length of the sides, front, and back (sometimes referred to as "bibs"); and ventilation areas. Some heavyweight hood materials use mesh materials in the ear region to permit easier communication, but this feature also reduces protection. One style of hood uses mesh on the top of the hood (sitting underneath the helmet) to provide a means for heat to escape.
Some of the reluctance to use hoods has been due to resistance by some firefighters to the idea of total encapsulation of the body. Many more traditional firefighters claim that they use their ears as "early warning" sensors to detect excessive heat and know when to leave. Unfortunately, the sensitivity of ears to heat also makes them very vulnerable to high heat. Hoods have repeatedly demonstrated their effectiveness in covering those exposed portions of the face not covered by other elements of the ensemble.
Check back for part two of this series, which will address gloves and footwear as the other two primary elements of the firefighter protective ensemble.
