When a chain saw strikes chain saw chaps, Kevlar ﬁ bers are pulled into the chain saw’s drive sprocket, slowing and quickly stopping the chain.
A back-coated nylon shell covers the Kevlar protective pad inside the chaps. The shell resists water, oil, and abrasions. The protective pad consists of ﬁ ve layers of Kevlar in the following order: woven Kevlar, felted Kevlar, woven Kevlar, woven Kevlar, and felted Kevlar. Kevlar is an aramid ﬁ ber similar to the Nomex material used in ﬁ reﬁ ghter’s clothing. Kevlar is more resistant to ﬂ ame than Nomex. When chain saw chaps are exposed to temperatures higher than 500 degrees Fahrenheit, the nylon shell may melt, but the protective Kevlar pad will not burn.
Chain saw users shall wear chaps. Chain saw chaps need to be adjusted properly and worn snug to keep them positioned correctly on the legs. The chaps should provide coverage 2 inches below the boot tops. Proper ﬁ t and correct length maximize protection.
Chain Saw Chaps Speciﬁ cations (6170–4)—The Forest Service has provided cut-resistant protective chaps for chain saw sawyers since 1965. Chain saw chaps have prevented thousands of serious injuries.
The protective pad in the original Forest Service chain saw chaps consisted of four layers of ballistic nylon. Tests of chain saw chaps conducted by the Missoula Technology and Development Center (MTDC) concluded that four layers of ballistic nylon offered protection to a chain speed of 1,800 feet per minute without a cut through. In 1981 Forest Service chain saw chaps were redesigned to improve the level of protection to a chain speed of 2,500 feet per minute without a cut through. The weight of the chaps was reduced by 40 percent, making them more comfortable.
The center monitors chain saw injuries. Because chain saws require right-hand operation, the majority of chain contact injuries occur on the left leg. In 2000, the Forest Service chain saw chaps were redesigned. The new design provides protection to a chain speed of 3,200 feet per minute without a cut through and increases the area of coverage for the left side of the left leg by about 2½ inches, and for the left side of the right leg by about 1½ inches. The higher level of protection and larger area of protection increased the weight of each pair of chaps by 6 to 8 ounces, depending on the length (32, 36, or 40 inches). Only saw chaps provided by the General Services Administration that meet the most current Forest Service speciﬁ cations (6170–4) are approved for purchase and use by Forest Service employees.
Inspection and Replacement Chain saw chaps need to be inspected and replaced when appropriate. Replace chain saw chaps when:
• The outer shell has numerous holes and cuts. Holes in the outer shell allow bar oil to be deposited on the protective pad. The oil acts as an adhesive, preventing ﬁ bers in the pad from moving freely, decreasing the protection.
• Wood chips and sawdust are evident in the bottom of the chaps.
• Repairs have stitched through the protective pad. Machine or hand stitching the protective pad prevents the ﬁ bers from moving freely, decreasing the protection.
• Cleaning has been improper. Detergents with bleach additives decrease the protection.
• High-pressure washing has destroyed the protective pad.
• The chaps have a cut that is more than 1 inch long in the ﬁ rst layer of yellow Kevlar.
Caring for Chain Saw Chaps Treat your chain saw chaps as a CRITICAL piece of safety equipment. Keep them as clean as possible. Appropriate and timely cleaning reduces the ﬂ ammability of the chaps and keeps them from soiling your clothing. Do not use your chaps as a chain stop.
Use Citrosqueeze, a commercially available citrus-based cleaning product, to clean chain saw chaps. Citrosqueeze has been tested and approved by Dupont for cleaning Nomex and Kevlar. Do not machine wash or machine dry chain saw chaps.
Cleaning Chain Saw Chaps
Hose and brush off chain saw chaps to remove dirt. Citrosqueeze must be diluted before use.
• For light soiling, use a Citrosqueeze solution in a spray bottle (mix 1 part Citrosqueeze concentrate to 10 parts water). Spray solution on the area to be cleaned and brush the solution into the chaps with a bristle brush. Wait one-half hour, thoroughly rinse the chaps with cold water, and allow them to air dry.
• For heavy petroleum contamination, soak chain saw chaps in Citrosqueeze solution for a minimum of 4 hours, overnight if possible. Brush the chaps with a bristle brush, rinse them thoroughly with cold water, and allow them to air dry. Many pairs of chain saw chaps can be cleaned in a single soak tank. Use 10 to 15 gallons of solution in a soak tank.
Clean all chaps before repairing them. Repair cuts and holes in the outer shell as soon as possible to prevent the protective Kevlar pad from becoming contaminated with bar oil and petroleum products.
When repairing damage to the chaps’ nylon shell, use a commercially available product called Seam Grip. Seam Grip provides a ﬂ exible, waterproof, and abrasion-resistant patch that will prevent petroleum products from contaminating the protective Kevlar pad.
Remove chain saw chaps from service if they have a cut longer than 1 inch in the top layer of Kevlar.
To repair holes and tears in the nylon shell:
• Cut a piece of notebook or printer paper that extends about 2 inches beyond the edge of the damage.
• Slip the paper inside the hole or tear so the paper lies on top of the protective Kevlar pad.
• Lay the chaps on a ﬂ at, level surface and press the nylon shell onto the piece of paper.
• Squeeze Seam Grip onto the paper and onto the sides of the tear so there is good coverage on all sides of the tear or hole.
• Allow the patch to dry for at least 12 hours before using the chaps.