Temporary instability of heavy items
Some maintenance activity may involve the temporary suspension of a heavy item, or its movement to another part of the workplace for temporary storage or disposal. This activity is often carried out infrequently, or is a 'one-off', and will require careful pre-planning - necessitating more knowledge and skill than routine production tasks. Consequently, these activities need to be properly planned by a competent person who has both practical and theoretical knowledge, and who has relevant experience.
While temporarily supporting a heavy item, factors to take into account include:
- The weight of the item and the strength of the temporary support to hold the load, eg, roof trusses have sometimes been used without considering the effect of the additional loading;
- The stability of a temporary support to hold the load, eg, narrow base supports have sometimes been used which can easily tip over if the load is not centred, or if the support or item moves because the ground is soft or not level;
- The nature of the item to be supported, including its centre of gravity, especially when supporting machinery which may be heavier at one side (which creates the possibility of the item swinging when lifted, or of sliding off its supports when lowered);
- The need for additional supports secured in position, eg, where the primary support is by hydraulic jacks or rope lashings, and especially where people have to work under a suspended load;
- The need to secure narrow-base freestanding items from slipping or toppling, eg, steel floor plates propped against a wall, and
- The inability of people to prevent the movement or fall of a heavy item and their often instinctive reaction to try to catch or stop a falling item.
While moving a heavy item in the workplace factors to take into account include:
- The stability during movement. If you intend to use a forklift truck consider: its load capacity; the size of the item in comparison to the width of the forks (over-hang); the risk of the load slipping or tipping (especially where the centre of gravity is at one side); the speed of movement where corners are turned, or where there are inclines. If you intend to use an overhead travelling crane consider the risk of swinging of the load due to eccentric loading or momentum;
- The risk of disturbing adjacent items either due to insufficient clearance or the effect of removing the weight of the item being moved on the balance of others;
- Keeping the route clear of people and other traffic, and
- The inability of people to hold a heavy load in position or prevent its movement or fall, and their often-instinctive reaction to try to catch or stop a falling item.
HSE has produced guidance on the Lifting Operations and Lifting Equipment Regulations 1998, but there are no specific regulations or HSE guidance covering the temporary suspension of a heavy item or its movement to another part of the workplace.