Safety Latches for Hooks
I was recently asked a question about whether it was acceptable to use a hook without a safety latch and if so was this not in contravention of section 4 of Driven Machinery Regulation 18 from the Occupational Health and Safety Act. The answer like most scenarios in the Lifting and Rigging industry is more complex than a simple yes or no answer. Anchor Industries does not xstablish recommendations for when a hook latch is required, these are outlined by the OHSA, the application, product standards and industry practises.
Let’s start by looking at the wording of section 4 of DMR 18 from the South African Occupational Health and Safety Act:
The user shall cause every hook or any other load- attaching device that forms part of the load path of a lifting machine or hand-powered lifting device to be so designed or proportioned that accidental disconnection of the load under working conditions cannot take place.
This means that every hook or load-attaching device that forms part of the lifting machine under stress during the lifting operation must be designed such that the load cannot be accidentally disconnect under working conditions. The best way to ensure this is for the hook to be fitted with a safety latch to bridge the throat opening but this isn’t the only method as the users could splice a small piece of rope across the throat of the hook, this is known as “mousing”.
ANSI/ASME Standards for Hooks
ANSI/ASME B30.10-2005 Hooks states, “When a latch is provided, it shall be designed to retain such items as, but not limited to, slings and chains under slack conditions. The latch is not intended to support the load.” Hooks are to be frequently inspected for “latch engagement (if provided)” and “damaged or malfunctioning latch (if provided)”. “When using a device to close the throat opening of the hook, care shall be taken that the load is not carried by the closing device.” “The use of a hook with a latch does not preclude the inadvertent detachment of a slack sling or a load from the hook. Visual verification of proper hook engagement is required in all cases.” “When a lock is equipped with a latch, the latch should not be restrained from closing during use.”
Note that the above requirements are applicable to only the hooks that support a load in a direct-pull configuration where the load is carried in the base (bowl/saddle or pin hole) of the hook. These requirements are not in the chapter that is applicable to hooks that do not support load in a direct-pull configuration, such as a grab or choker hook.
ANSI/ASME B30.9- 2006 Slings does not specifically address the requirement of latches on hooks used on slings. It consistently refers to B30.10 for hook component characteristics, removal criteria, and repair, of chain slings, wire rope slings, synthetic rope slings, synthetic webbing slings, synthetic round slings.
ANSI/ASME B30.5-2004 Mobile Cranes states “Hooks shall be equipped with latches unless the application makes the use of a latch impractical. When provided, the latch shall bridge the throat opening of the hook for the purpose of retaining slings or other lifting devices under slack conditions (refer to ASME B30.10).”
ANSI/ASME B30.23-2005 Personnel Lifting Systems states “Hooks used for attachment of a personnel lifting platform shall be of a type that can be positively locked closed and that will prevent the platform lifting bridle from being dislodged.”
ANSI/ASME B30.2-2005 Overhead and Gantry Cranes states “Latch-equipped hooks shall be used unless the application makes the use of the latch impractical or unnecessary.” “When required, a latch or mousing shall be provided to bridge the throat opening of the hook for the purpose of retaining slings, chains, or other similar parts, under slack conditions (see ASME B30.10).”
ANSI/ASME B30.21-1999 Manually Operated Hoists states “Hooks shall be equipped with latches unless the use of the latch creates a hazardous condition where it interferes with the use of the hook. When required, a latch shall be provided to bridge the throat opening of the hook for the purpose of retaining slings, chains, etc., under slack conditions. (See ASME B30.10).” Under Frequent Inspection, “hook latches, if used, for proper operation.” Under Operation, “The sling or other device shall be properly seated in the base (bowl) of the hook. Hook latch shall not be allowed to support any part of the load.”
API Specification 2C Specification for Offshore Cranes Sixth Edition, Sept. 2004 states, “Hooks shall be equipped with a latch to retain loose lifting gear under non-lifting conditions. The latch shall be lockable if the hook is to be used for transporting personnel. The latch is not intended to support the lifted load.”
As you can see it can be confusing to determine when a safety latch must be used but it’s really about being sensible and safe and a safety latch doesn’t guarantee that. You do that by making sure you’re using quality products, your staff are well trained and you have proper work procedures. If for example the oblong of a sling doesn’t seat completely into the crane hook, no safety latch can make it safe to use and sometimes we get caught up in the specifics while missing the bigger picture.