OSHA rules and NFPA standards make the use of rubber insulating products mandatory when even the smallest probability of contact with 50 volts AC or higher exists. These rules affect nearly all industrial workplaces, as every single facility (including utility contractors and general contractors) has a need for electrical safety and arc flash protection, and failure to comply can result in heavy fines, serious injury and even death. Moreover, OSHA and ASTM standards also require regular inspection and testing of in-service electrical protective equipment in order to maintain compliance and ensure the products’ safety and integrity when exposed to a wide range of voltages.
After a visual inspection is completed, rubber goods should be electrically tested, at their rated test voltage, using specialized equipment designed to gradually increase the voltage to the desired test level. The dielectric test is two-fold: Pass/fail on the ability to withstand the rated test voltage and, for gloves, quantitative on the ability to prevent electric current from passing through the rubber goods above the maximum contained in the specifications. Products passing the inspection and test procedures can then be returned to service.
Testing is a critical component to electrical safety in that not only does it help maintain compliance, but it also helps to increase savings. ASTM F496 (insulating gloves and sleeves), ASTM F478 (insulating line hose and covers) and ASTM F479 (insulating blankets) specifications apply to the in-service care of rubber insulating products. Moreover, rubber insulating products are costly, and many times these costs are unnecessarily increased by purchasing replacements for products that could have remained in service with the proper in-service care, testing and recertification.
At a minimum, ASTM standards require that the inspection and testing process include the following steps:
- Removing previous testing marking
- Washing using cleaning agents that will not degrade the insulating properties
- Visual inspection of all surfaces (inside and out)
- Electrical testing
- Final inspection
- Packing in appropriate containers (“appropriate containers” means boxes, or similar sturdy packaging materials to prevent folding, creasing or similar loose storage that can cause stress on the rubber) for storage or shipment
When selecting a test lab, make sure that it is a NAIL-accredited test lab. NAIL stands for National Association of Independent Laboratories for Protective Equipment Testing (www.nail4pet.org). It incorporates the only Laboratory Accreditation for the electrical equipment test labs program in North America. NAIL4PET helps develop uniformity in testing and works in close association with the American Society of Testing Materials (ASTM International).
The interval between the date of issue and electrical testing should be based on work practices and test experience. For gloves, the interval shall not exceed 6 months except for industries such as telecommunications that utilize insulating gloves as precautionary protection, in which case the maximum interval may be increased to 9 months. For sleeves and blankets, the interval shall not exceed 12 months. For line hose and covers, no minimal maximum interval is specified; Electrical testing shall be performed if the periodic cleaning and visual inspection identifies conditions that might adversely affect performance and safety.
Keep in mind that all electrical protective rubber insulating products are tested by the manufacturer prior to the first shipment. End users (or an end users’ designee) may perform acceptance testing within the first 2 months after receipt. However, do not place rubber insulating products into service unless they have been tested electrically within the previous 12 months.
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