Working at height means work off the ground and commonly involves using scaffolds, ladders, hoists, gantries or general roof work.
Work on a roof is particularly dangerous and levels of control will depend on whether the roof has edge protection, is allied to the plant or has rooflights. A useful control measure is to ask contractors for a method statement covering:
Access to the roof must be restricted - doors leading to it must be kept locked and a permit to work may be appropriate. For unguarded roofs a safety barrier away from the edge should be used to identify work areas and safe access routes. Walkways across the roof should have a barrier each side. Where plant or equipment is within two metres of an unprotected edge a barrier must be put up to prevent falls. Roofs built of fragile materials must only be accessed by roof ladders or crawling boards and a fall arrest device must be in place. Rooflights are a hazard, as they are not load bearing. They must be clearly marked or painted and protected by barriers where possible. Netting, sheeting or fans should be used to protect pedestrians from falling debris. In some circumstances, it may also be necessary to fence around the working area at ground level. Debris must never be thrown from height and chutes or baskets must be used.
Scaffolds may be fixed, tower or mobile. Fixed scaffolds should be erected, secured to a permanent structure and inspected by a competent person. They must be based on solid ground with working platforms wide enough to allow safe working. The platform must be capable of withstanding loads put upon it. Guard rails and toe boards must be provided. Tower and mobile scaffolds must, in addition, be erected with the base to height ratio to ensure stability. Wheels and outriggers must be locked before use and the scaffold must not be moved with people on board. The safe working loads marked on the base must never be exceeded.
Ladders may be fixed or freestanding and must be considered a second best option. Alternatives such as tower or mobile platforms provide a safer access. Fixed ladders must incorporate a landing no more than six metres apart and back hoops must be fitted more than 2.5 metres high. Ladders must be fitted with boarding or a device to prevent unauthorised access. Where the ladder provides access to an unprotected roof there must be barriers of at least two metres each side at roof level. All ladders must be checked for solid rungs and straight sides before they are used. Wooden ladders must never be painted. Boarding or cones must protect ladder feet and any extensions must overlap by at least three rungs. Ladders must be secured with eyebolts and hooks or by another person stabling/footing the ladder if it is less than five metres high. Always use the one in four rule - one foot out for every four up and never work higher than one metre from the top rung.
Elevating platforms must never be left unattended when in use. Work must be undertaken from within the platform only and it must never be moved with people on board. Warning signs, cones or safety barriers must be placed around its base. Window cleaners and building maintenance teams use access cradles. As they are potentially dangerous, there must be a safe way of getting in and out of them. People in them must be harnessed at all times and if working over pedestrian routes tools must be secured by lanyards. There must be a means of communication between the cradle and the operators by mobile phone or a similar device. Platforms and cradles will need an independent thorough examination by an engineer every six months.
You can see more information on the HSE website http://www.hse.gov.uk/work-at-height/index.htm .