Ten months into the promulgation of the new NFPA 1970 standard (issued September 2024), some of the first products to be certified will be making their way into the market shortly — and protective hoods are likely to be in the initial rollout. Given the number of changes to hood requirements that were contemplated during the standard revision process and on to the final criteria that was adopted, firefighters will note some changes in the offering of hood products from initial discussions in 2023 (Read: Firefighter protective hoods: An ongoing evolution amid NFPA 1971 changes). With new hood products entering the market, let’s review what the fire service should expect and how to determine which hoods may best fit a department’s operational needs.
What’s new for hoods?
By far, the most significant change for the new NFPA 1970 standard is the mandatory requirement that structural firefighting hoods have particulate-blocking capabilities. These capabilities are achieved by a separate type of barrier layer that effectively blocks soot particle passage. Associated with this mandate is a requirement that structural protective hoods have a total heat loss that is 325 watts per square meter. To put this in perspective, all new structural firefighting hoods must have a filtering capability that blocks 90% of the particles that are 0.1 to 1.0 microns in diameter that flow through the hood material composites. They must also have much greater breathability than the minimum requirement for garments composites at 205 W/m2 (the best performing garment composite barely reach 325 W/m2). These requirements apply to structural firefighting hoods going forward with the new edition.
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Compared to the 2018 edition of NFPA 1971 where the optional particulate-blocking hoods were first introduced, particulate-blocking (filtration) requirements are slightly more robust in that the seams of hood composite materials must also now be tested. Most of the other performance requirements that had been applied to all hoods (particulate blocking or not) — including thermal protective performance (TPP), flame resistance, heat/thermal shrinkage resistance, cleaning shrinkage, burst strength, seam strength, and hood opening size retention — remain essentially the same for new NFPA 1970 hoods.
There are two additional new requirements for manufacturers to conduct tests — measurement of transmitted and stored energy, and contaminant removal efficiency — that are new tests but only for manufacturers to report the results without having to meet any specific criteria.
Protective hoods for proximity firefighting ensembles are held to the same performance as the older NFPA 1971 (2018 edition) non-particulate-blocking hoods.
From a design perspective, the new NFPA 1970 structural particulate-blocking hoods will require filtration capability over nearly the entire surface of the hood. Before, the optional particulate-blocking hood material layer did not have to be present at the top of the hood (generally under the helmet) or in much of the bib area that tucks underneath the top of the coat. In the new NFPA 1970 standard, there are now minimal sizing requirements where offered hoods must be designed to fit a large range of the firefighting population in terms of key head dimensions, which may mean multiple sizes will have to be offered for some of the less elastic hood products.
Lastly, restricted substance requirements will be applied for minimizing levels of hazardous chemicals in the manufactured hood materials. Manufacturers will further be able to label hoods that do not contain intentionally added PFAS chemicals if, after testing, they have a concentration of total fluorine of less than 100ppm as defined by NFPA 1970. These new criteria also pertain to other elements of the structural protective ensemble.
How will the new hood requirements affect available products?
Fire departments that have already switched to particulate-blocking hoods may not notice much difference between new hoods, depending on the products they already use. However, there may still be subtle changes, particularly with required seam filtration, complete particulate-blocking capability on the overall hood, and overall hood fit criteria. Since the prevention of particle passage through seams may require taping or sealing seams for some material systems in combination with full-scale coverage of the blocking layer, there are likely to be noticeable differences for how well some hoods might conform to the wearer’s head. These new requirements may also affect how the hood interfaces with the other ensemble items (helmet, coat and SCBA facepiece). In theory, the new requirements are supposed to provide better and more consistent coverage.
For departments that have not transitioned to particulate-blocking hoods and currently rely on full-knit hoods, the contrasts will likely be much starker but will also be based on what types of hoods departments have formerly worn before the change. Firefighters that have worn the two- or three-layer traditional knit hoods will notice a substantial difference in flexibility and stretch in hood products. Firefighters who have used thicker hoods, which often had three-layer knit construction, will have less heat protection to compensate for mandatory minimum breathability for all hoods.
There are other ergonomic issues that may be observed but are more affected by the number and choice of material layers as well as the overall design of the hood. Comprehensive investigations of hood performance, including their effects on end-users, are reported in two free-access, multi-institutional studies:
- “Impact of firefighter hood design on range of motion, noise production, and hearing”
- “Effects of firefighting hood design, laundering, and doffing on smoke protection, heat stress, and wearability”)
The first study found that particulate-blocking hoods could reduce a firefighter’s range of head motion. As expected, thicker hoods reduce a firefighter’s ability to hear the outside environment, including radio communications, which can be further impacted by the type of particulate-blocking layer used in the hood’s construction. It was also found that certain types of particulate-blocking layers would increase the amount of noise, which, in turn, interferes with firefighter hearing.
The second study surprisingly found that firefighter exposure to polycyclic aromatic hydrocarbon (PAH) contaminants was more affected by the way hoods were doffed following exposure rather than certain material or design factors. Specifically, an overhead motion for removing the hood from the firefighter’s head with the SCBA facepiece still worn always resulted in significantly less neck contamination than the more traditional method of pulling the hood down to the firefighter’s neck to allow access to the facepiece straps with subsequent pulling of the hood over their face. The study also examined differences between new knit hoods, new particulate-blocking hoods and laundered particulate-blocking hoods. The study found new particulate-blocking hoods had a slight advantage reducing particulate exposure over laundered particulate-blocking hoods. Additionally, particulate-blocking hoods performed better compared to new knit (non-particulate-blocking hoods) in reducing exposure.
The second study did not find significant differences in skin temperature, core temperature, heart rate or subjective wearability ratings for the different types of hoods. However, it must also be pointed out that the study did not provide a comprehensive comparison between the many hood material systems and design configurations available in the marketplace.
Again, for traditional hood-wearers moving toward particulate-blocking hoods, perceptions will be tempered by what they are used to in their current hood practices. Departments that have worn heavier, more insulative hoods are likely to find the new hoods offering less thermal protection but perhaps more comfort. Organizations that have worn conventional two-layer hoods may perceive particulate-blocking hoods as more cumbersome and harder to fit. Depending on the differences in hood materials and design, there can be changes to thermal perception, comfort, ease of head motion, noisiness, ability to hear, general fit, interface effectiveness and donning/doffing ease.
As noted above, the new standard has new optional reporting requirements for stored/transmitted heat energy and ease of decontamination. These test results are report-only measurements that are not yet fully understood. As this data becomes available on new products, manufacturers and independent experts will need to provide explanations for how to interpret this information and its significance in understanding hood performance and care.
Which factors should be considered in choosing hoods?
Any change to a newly available product, particularly when a mandatory change is dictated in the prevailing standard, requires the fire department to reevaluate their specific protection needs and understand how the new product fits with their tactics, current experience and overall expectations. Believing that there is a one-to-one even exchange is generally a mistake that can lead to potential injuries. Departments should assess various factors by asking the following questions related to a potential new product as compared to an incumbent product:
- What is the TPP of the hood material composite? Is it uniform over the entirety of the likely exposed area?
- What is the breathability of the hood material composite? What is the overall comfort for wearing the hood, particularly under hot/humid ambient and fireground conditions?
- What filtration levels do the hood materials provide against micro-sized particles?
- How easy is it to put the hood on and take it off? Do the department procedures for removing the hood lead to contact with contaminated exterior sources?
- How does the hood affect head movement, the ability to hear and the perception of external heat?
- Does wearing the hood make noise (such as “crackling” sounds) from head movement that further interferes with hearing?
- How well does the hood interface with the other ensemble items (SCBA facepiece, helmet suspension/ear covers, and protective coat, particularly the collar and collar closure)?
- How well does the hood hold up to repeated use? Does the hood opening maintain its shape sufficiently to fit snugly around the SCBA facepiece?
- Does frequent laundering diminish hood performance or damage materials? How many uses with cleaning can be anticipated?
- How easy is it to clean the hood? Are available cleaning techniques effective in removing fireground soils and contaminants?
- Does the hood contain unacceptable levels of restricted substances?
Some of the answers to these questions can be obtained from manufacturers, others from fire departments, which may have experience with the product; however, the best answers often come from trials using the new product in concert with the organization’s standard operating procedures.
All these factors interact with firefighter training, experience and tactics. Any consideration of a new product must demonstrate how the new hood integrates withing the total ensemble’s overall operational performance and function. Where differences are discovered, it may be necessary to retrain firefighters for any differences in performance, particularly limitations relative to old practices.
When do the new hoods have to be used?
Your department generally makes the decision about what PPE you are required to use. They have the responsibility to select appropriate PPE based on their assessment of the hazards and risks faced by their members. At the time of publication, an amendment to NFPA 1970 was likely to go into effect to extend the grace period permitting the sale of firefighter PPE meeting the older 2018 standard through mid-March 2026. Any hoods sold up to that date remain certified according to the NFPA standard that existed at the time the product was manufactured. Hoods produced during the grace period, or before, remain certified until retired. However, in March 2026, all new hoods manufactured will need to comply with the new NFPA 1970 requirements.
Note: The views of the author do not necessarily reflect those of the sponsor.
