Definitions and Customer Considerations
Maximum Working Load (M.W.L.)
Maximum Working Load (M.W.L.) is the maximum static and/or dynamic load at which the product will still function without excessive friction, distortion, wear or permanent deformation of components. Above this load, bearing systems may fail, moving parts may seize and stainless steel or plastic components may begin to bend, stretch or otherwise deform. Maximum working loads should never exceed half of the breaking load, and should never be exceeded in use.
Breaking Load (B.L.)
Breaking Load (B.L.) is the load at, or around which, a major failure can be expected to occur to some part of the product’s structure when new. Plastic components may split, rivets may give way, shackles may break, and other metallic components may fracture. No product should be used at more than half of the breaking load, so as to provide a minimum safety factor of two (2).
Factor of Safety
An appropriate factor of safety should be applied to Breaking Load figures to suit each application before choosing or specifying a particular product. For many industrial and safety related applications, and for some yachting applications, a factor of safety greater than two (2) should be used or may be required by law or other regulations. It is the customer’s responsibility to ensure that an appropriate factor of safety is used, and it should allow for factors including but not limited to safety implications, service life, fatigue (as may be caused by wave action, wind stresses or repetitive cyclical loading), type of load (e.g. cyclic, shock, rotational speed), orientation of load, environment (e.g. exposure to ultraviolet light, temperature extremes), corrosion and stress corrosion. Note that a ‘safe working load’ is not specified as this is dependent on the factor of safety, which must be determined by the user relative to each application.
The useful life of any product is determined by the above factors and must be assessed in each application, and thus no guarantee can be provided for product life, load capacity or any other factor due to the variability in usage. In some jurisdictions government regulations require the replacement of rigging components within certain periods of time, usually every three to five years. You must ascertain whether any such regulations affect you. While every precaution is taken in the product design and manufacturing processes to minimize the effects of corrosion and stress corrosion, there are also preventative as well as corrective treatments that can be carried out after installation. Contact your local representative for further assistance and advice.
Product Information Amendments
All catalog information is subject to specification changes during a product’s life-cycle. Any alterations will be posted on the website - www.ronstan.com, which should be considered the most up to date source of product information.