What Does OSHA 1910.137 Say About Rubber Insulating Matting?
If you only need the direct answer, here it is: OSHA 1910.137 does apply to rubber insulating matting. The standard treats it as electrical protective equipment and addresses how it should be marked, how its class and type should be identified, and how its electrical performance should be evaluated. OSHA also recognizes ASTM D178 as a standard that is deemed to meet the performance requirements for rubber insulating matting. At the same time, OSHA’s test-interval table does not separately list matting the way it lists gloves, blankets, sleeves, covers, and line hose, and OSHA has also stated in an interpretation letter that retesting of rubber insulating matting is not required, provided employers keep it in a safe, reliable condition through measures such as visual inspection.
Quick Answer at a Glance
- Yes, OSHA 1910.137 covers rubber insulating matting. It is named directly in the regulation.
- It must be clearly marked by electrical class and by type, including Class 00, 0, 1, 2, 3, or 4 and Type I or Type II where applicable.
- It must meet electrical performance requirements. OSHA says the proof test must reliably show that the equipment can withstand the voltage involved, and for matting the test duration is 1 minute, not 3 minutes.
- ASTM D178 is the key recognized standard for rubber insulating matting under OSHA 1910.137.
- It is not the same thing as a ground mat under OSHA 1910.269 Appendix C, which describes a metal mat used to create an equipotential zone.
- Do not assume glove or blanket retest intervals apply to matting. OSHA’s Table I-5 does not separately list matting, and OSHA has expressly said retesting of rubber insulating matting is not required.
What OSHA 1910.137 Clearly Covers
OSHA 1910.137 begins by listing the specific types of electrical protective equipment covered by its design requirements. That list includes rubber insulating blankets, rubber insulating matting, rubber insulating covers, rubber insulating line hose, rubber insulating gloves, and rubber insulating sleeves. This matters because it immediately separates true electrical insulating matting from ordinary rubber floor products. In practical terms, a product should not be treated as OSHA-type insulating matting simply because it is made of rubber.
The regulation then moves into manufacture and marking. For rubber insulating equipment covered by paragraph (a), OSHA requires each item to be clearly marked by class. The standard lists Class 00, Class 0, Class 1, Class 2, Class 3, and Class 4. It also requires non-ozone-resistant equipment to be marked Type I and ozone-resistant equipment to be marked Type II. OSHA further says the markings must be nonconducting and must not impair the insulating qualities of the equipment. For buyers, this is one of the fastest first-screen checks: if class, type, and proper nonconductive marking are unclear, the product is already weak from a compliance standpoint.
What OSHA Requires for Electrical Performance
OSHA 1910.137 also addresses the electrical requirements for rubber insulating equipment. The standard says the equipment must be capable of withstanding the relevant AC or DC proof-test voltage, and it adds an important detail for matting: the proof-test voltage must be applied continuously for 3 minutes for equipment other than matting and for 1 minute for matting. That difference is easy to miss, but it is central when you evaluate product literature, lab procedures, or supplier claims.
OSHA then ties compliance to recognized standards. In the note to paragraph (a), OSHA states that rubber insulating equipment meeting certain national consensus standards is deemed to comply with the performance requirements of the regulation. For rubber insulating matting, the cited standard is ASTM D178-01 (2010), Standard Specification for Rubber Insulating Matting. OSHA repeats ASTM D178 again in the note to paragraph (c)(2)(ix) as a standard electrical test method considered to meet the rule. In procurement terms, ASTM D178 is not a marketing extra. It is the key technical anchor buyers should ask for when they need rubber insulating matting that aligns with OSHA’s framework.
What OSHA Does Not Say the Way Many Buyers Assume
This is where many product pages and distributor listings become inaccurate. OSHA 1910.137 contains a test-interval table, Table I-5, that gives maximum intervals for periodic electrical tests. However, the table separately lists rubber insulating line hose, covers, blankets, gloves, and sleeves. It does not separately list rubber insulating matting. That means buyers should be careful not to copy the glove or blanket schedule into matting specifications without checking the actual OSHA text.
OSHA has made this point even clearer in an official interpretation letter dated July 12, 1996. In that letter, OSHA confirmed that retesting of rubber insulating matting is not required. At the same time, OSHA did not give employers a free pass. The agency said employers must institute measures, such as visual inspections, to ensure the matting is maintained in a safe and reliable condition. This is the right operational takeaway: no fixed retest interval does not mean “no condition control.” It means the compliance burden moves toward inspection, care, storage, and removal from service when defects appear.
Rubber Insulating Matting Is Supplementary Protection
Another point worth stating directly: OSHA materials treat rubber insulating matting as supplementary or secondary protection, not as a stand-alone substitute for the rest of an electrical safety program. In the 1996 interpretation letter, OSHA said rubber insulating matting is intended for supplementary use with other appropriate electrical protective equipment. In an OSHA Safety and Health Information Bulletin, the agency also described rubber insulating matting as an example of secondary electrical protection, while identifying gloves and blankets as examples of primary protection. For users in the field, the message is straightforward: insulating matting can be important, but it should not be marketed or selected as the only control between the worker and electrical risk.
Rubber Insulating Matting Is Not the Same as a Ground Mat
This distinction deserves its own section because the two products are often confused in search results and even in catalog language. Under OSHA 1910.269 Appendix C, a ground-level equipotential zone can be established through the use of a metal mat connected to the grounded object. That is a very different concept from rubber insulating matting under 1910.137. One is part of an equipotential grounding strategy. The other is part of an insulating protective equipment framework. If a supplier uses these two terms interchangeably, that is a serious warning sign.
What Buyers and Safety Teams Should Check in Practice
When you review rubber insulating matting for actual use, the first checkpoint is identification. Ask whether the product is presented and marked as electrical protective equipment, not merely as industrial rubber flooring. The class marking, type marking, and the underlying standard reference matter because OSHA 1910.137 treats this as a controlled category of protective equipment.
The second checkpoint is test and standard evidence. A serious supplier should be able to connect the product to ASTM D178 and explain how proof testing is carried out for insulating matting. The documentation should be specific enough to support the claim, not just a generic phrase like “high voltage resistant” or “electrical safety mat.”
The third checkpoint is condition control after delivery. OSHA says electrical protective equipment must be maintained in a safe, reliable condition. It also lists defect categories that make insulating equipment unacceptable for use: holes, tears, punctures, cuts, ozone cutting or ozone checking, embedded foreign objects, swelling, softening, hardening, stickiness, inelasticity, or any other defect that damages insulating properties. Even where the rule’s specific in-service clauses focus on other rubber insulating items, these defect concepts are still highly relevant to how matting should be inspected and managed in the field.
The fourth checkpoint is storage. OSHA says insulating equipment must be stored in a way that protects it from light, temperature extremes, excessive humidity, ozone, and other damaging substances and conditions. This is one of the most overlooked issues in real use. A technically compliant product can still become a weak link if it is folded badly, left near ozone sources, stored in harsh sunlight, or handled as if it were ordinary shop flooring.
A Practical Reading of OSHA 1910.137
If you read OSHA 1910.137 from a user’s perspective rather than a lawyer’s perspective, the standard says five practical things about rubber insulating matting.
First, it is a recognized category of electrical protective equipment. Second, it must be correctly marked and correctly specified. Third, it must meet a real electrical performance framework, with OSHA recognizing ASTM D178 as the core route. Fourth, it should be treated as supplementary protection, not as the only safeguard. Fifth, it must stay in safe, reliable condition, even though OSHA does not separately assign it the same fixed retest interval structure used for gloves and some other rubber insulating items.
FAQ
Does OSHA 1910.137 apply to rubber insulating matting?
Yes. OSHA 1910.137 directly names rubber insulating matting in the section covering design requirements for specific types of electrical protective equipment.
Does OSHA require periodic retesting of rubber insulating matting?
OSHA’s Table I-5 does not separately list matting, and OSHA stated in an interpretation letter that retesting of rubber insulating matting is not required. However, employers still have to maintain it in a safe, reliable condition, including by inspection and condition control.
Is ASTM D178 important for OSHA compliance?
Yes. OSHA names ASTM D178-01 (2010) as a national consensus standard deemed to comply with the performance requirements for rubber insulating matting, and it also lists ASTM D178 among recognized electrical test methods.
Is rubber insulating matting the same as a ground mat?
No. OSHA 1910.269 Appendix C describes a metal mat connected to a grounded object for an equipotential zone. That is different from rubber insulating matting covered by OSHA 1910.137.
What defects should take insulating equipment out of service?
OSHA lists defects such as holes, tears, punctures, cuts, ozone checking, embedded foreign objects, swelling, softening, hardening, stickiness, inelasticity, and any defect that damages insulating properties. These are critical inspection points for any serious electrical protective equipment program.
Closing
The most important procurement lesson is simple: rubber insulating matting is not just a rubber mat with an electrical-sounding label. Under OSHA 1910.137, it sits inside a defined electrical protective equipment framework. That means buyers should check the product’s class and type marking, standard basis, proof-test logic, storage guidance, and inspection condition—not just thickness, color, or price. When those basics are handled correctly, you have a much better basis for selecting matting that aligns with real workplace electrical safety requirements.
