1. Environmental factors such as an exposure to sunlight, dirt or gritty-type matter and cyclical changes in temperature and humidity can result in an accelerated deterioration of web slings. The rate of this deterioration will vary with the level of exposure to these conditions and with the thickness of the sling material.
  2. For example, single ply slings will generally degrade more rapidly with this exposure than multiple ply slings. All web sling slings that are exposed to these conditions should be highly scrutinized during their inspections.
  3. Web slings, when not in use, should be stored in a cool, dry and dark place to prevent loss of strength from exposure to sources of ultraviolet light. Web slings shall not be stored in chemically active areas and/or in areas where mechanical and/or environmental damage could occur.
  4. Chemically active environments can affect the strength of web slings in varying degrees ranging from little to total degradation. The web sling manufacturer, or a qualified person, should be consulted before web slings are used in a chemically active environment. In addition, water absorption can decrease the strength of nylon web slings by as much as 10-15%. Sling strength returns when the sling dries completely.
  5. Each chemical application shall be evaluated, taking into consideration the following:
    1. Type of acid or alkalis
    2. Exposure conditions, i.e., liquid, vapor, mist
    3. Concentration
    4. Temperature
    5. Duration of exposure
  6. ACIDS
    • Nylon is subject to degradation in acids, ranging from little to total degradation.
    • Polyester is resistant to many acids, but is subject to degradation, ranging from little to moderate in some acids.
  7. ALKALIS
    • Polyester is subject to degradation in alkalis, ranging from little to total degradation.
    • Nylon is resistant to many alkalis, but is subject to degradation, ranging from little to moderate in some alkalis.
  8. Nylon and polyester slings shall not be used in contact with objects or used at tempuratures in excess of 194°F (90°C) or at temperatures below minus 40°F (40°C).
  9. Web slings incorporating aluminum fittings shall not be used where fumes, vapors, sprays, mists or liquids of alkalis and/or acids are present, unless material compatibility is verified.
  10. Environments in which synthetic web slings are continuously exposed to sources of ultraviolet light can affect the strength of synthetic web slings in varying degrees, ranging from slight to total degradation.
  11. WARNING
    Slings used in environments where they are subjected to continuous exposure to sunlight or ultraviolet light shall be proof tested to twice the rated capacity semi-annually or more frequently depending on severity of exposure.
    Web slings that are used outdoors regularly should generally be permanently removed from service within a period of 1 to 3 years.
  12. CAUTION
    Degradation can take place without visible indications
    1. Factors which affect the degree of strength loss are:
      1. Length of time of continuous exposure.
      2. Web sling construction and design.
      3. Other environmental factors such as weather conditions and geographic location.
    2. Suggested procedures to minimize the effects of sunlight or ultraviolet light:
      1. When not in use, store web slings in a cool, dry, dark location free of mechanical and environmental damage.
    3. Some visual indications of environmental degradation are:
      1. Fading of webbing color.
      2. Uneven or disoriented surface yarn of the webbing.
      3. Shortening of the sling length.
      4. Reduction in elasticity and strength of the sling material due to an exposure to sunlight, often evident by an accelerated abrasive damage to the surface yarn of the sling.
      5. Breakage or damage to yarn fibers, often evident by fuzzy appearance of the web.
      6. Stiffening of the web, which can become particularly evident when web slings are exposed to outdoor conditions without being used or cyclicall tensioned.
  13. REPAIRS
    There shall be no repairs of sling webbing or stitching.