Health and Safety
Executive / Commission
Local authority circulars
To: Directors of Environmental Health/ Chief Environmental Health Officers of London, Metropolitan, District and Unitary Authorities and Chief Executives of County Councils.
For the attention of: Environmental Services / Trading Standards / Fire Authorities / Other
This circular gives advice to local authority enforcement officers
1 This circular includes a DATA SHEET which gives information on the use of vacuum lifting attachments, the various hazards encountered and the safeguards to be taken.
2 The Data sheet is intended as a working document for EHOs but it may be copied to employers and other persons.
3 HSE would be interested in unusual applications of vacuum lifting. If LA enforcement officers come across any unusual applications, details should be forwarded to HSE via the ELO.
| HEALTH AND SAFETY EXECUTIVE | HELA DATA SHEET HSE 234/3/100/7 |
|---|
1 This document contains internal guidance which has been made available to the public. The guidance is considered good practice but is not compulsory. You may find it useful in deciding what you need to do to comply with the law. However, the guidance may not be applicable in all circumstances and any queries should be directed to the appropriate enforcing authority.
2 This Data sheet is concerned with vacuum lifting attachments which utilise suction pads for the purpose of lifting loads and are used in conjunction with a lifting machine. It describes the use of these attachments, the various hazards encountered and safeguards which, in the Health and Safety Executive's opinion, should be taken when these attachments are used.
3 Vacuum lifting attachments have widespread use in the handling of materials, particularly plates of metal or glass, concrete slabs and pipes, etc. There are two basic types, the self-induced (non-powered) vacuum lifting attachment and the power operated vacuum lifting attachment.
4 This method of lifting is based on the simple 'suction cup' principle, where an inverted cup-shaped piece of rubber is pushed onto a suitable surface, expelling the air from beneath the cup. Atmospheric pressure on the underside of the surface will then hold the cup in place against a considerable vertical load. The vacuum can be broken by allowing air to enter the evacuated volume under the cup. In the simplest form the rubber cup with its handle and release valve can hold loads of up to about 35 kilograms.
5 Self-induced vacuum systems can be used for greater loads where the rubber cup is replaced by a metal cylinder with a flexible seal around its open end. Above the seal and within this cylinder is a piston, the top surface of which carries a rig for attaching to a crane hook. On lowering this device on to the surface of a load to be lifted, its own weight depresses the seal and the downward movement of the piston expels the air from the cylinder. On lifting, the piston is pulled upwards generating a vacuum within the space formed between the cylinder with seal and the surface being lifted. For loads with a large surface area, several suction cylinders may be used. Both single and multiple cylinder attachments may have many refinements. A valve can be fitted to allow easier escape of air on the downward stroke of the piston, whilst another valve can enable air to enter the evacuated volume when lifting has been completed so that the device can be removed easily. Both these valves can be operated either manually or automatically. Some attachments have an air operated warning whistle which sounds if the load is too heavy.
6 Power operated vacuum lifting attachments can take many forms. The power source, which may be an electric motor or an internal combustion engine, drives a vacuum pump which evacuates a reservoir tank fitted with a vacuum gauge. This reservoir is connected to a suction pad or series of pads which are similar to the cups. A control valve is located in the vacuum line between the reservoir and the lifting pad or pads. For maximum efficiency the power pack is located as close as possible to the lifting pads which are normally mounted on a metal frame. This frame can be formed of box sections suitably sealed and utilised as a reservoir. Greater flexibility in use can be introduced by fitting each pad with its own control valve. This enables the operator to select the required number of pads for any particular size of lift. The control valves are arranged so that the vacuum in the reservoir tank is applied between the pads and the load while lifting and air is admitted to the back of the pads to release the load.
7 Some powered attachments are built as self-contained units for attachment to the hook of a crane, while more permanent installations incorporate the attachment into a crane which may be either cab or floor operated. The complete attachment including power pack may be integrated with a process machine or flow line with its controls forming part of the main control console.
8 There are some vacuum lifting attachments of the powered type which obtain their vacuum by the use of either a venturi operating from an air line, or from a vacuum blower similar in principle to the domestic vacuum cleaner. The use of this type of equipment should be restricted to low weight and low height lifting applications due to the difficulty of incorporating the safety attachments discussed in paras 15-18.
9 Vacuum lifting attachments are not lifting tackle as defined in the Factories Act 1961 s.26 but they incorporate items which are included in that definition. All chains, rings, shackles, etc forming part of the vacuum lifting attachment are subject to the Factories Act 1961 s.26 or to the relevant regulations of the Docks Regulations 1988 or the Shipbuilding and Ship-repairing Regulations 1960. Vacuum lifting attachments are lifting accessories as defined by the Lifting Operations and Lifting Equipment Regulations 1998 and should therefore be thoroughly examined by a competent person at least every 6 months or in accordance with an examination scheme drawn up by a competent person.
10 A device which is integral with a crane is considered to be part of that crane and subject to the Factories Act 1961 s.27
11 When vacuum lifting equipment is used on construction sites the Construction (Lifting Operations) Regulations 1961 apply, and in particular Reg 49(1) requires the load to be adequately secured to prevent danger from slipping or displacement. In applications such as the lifting of industrialised building components which have to be raised high above the ground there is a risk that if the vacuum pump fails and there is high leakage, there may not be time to lower the load after the alarm rings. Therefore for high lift applications, ie above 10 metres, safety arms should be used. These arms should be engaged while the load is being lifted or some other effective means should be provided to prevent the load from falling in the event of loss of vacuum (see also para 21).
12 Some vacuum lifting attachments may be "relevant machinery" and others "interchangeable equipment", both will be subject to the Supply of Machinery (Safety) Regulations 1992, as amended.
13 It is recommended that vacuum lifting attachments should be dynamically tested in situ as a complete unit on the surface of the material which they are used to lift. The test should be carried out at the SWL of the assembly and should simulate the maximum acceleration/deceleration forces likely to be met in the particular application.
14 As a general rule the load stated by the manufacturer at which the vacuum attachment will not fail should be twice its SWL. The appropriate static proof test for a vacuum lifting attachment is also, as a general rule, equal to twice its SWL. Where a vacuum lifting attachment is mounted as an assembly on a lifting beam, the proof test values normally recommended for lifting beams should be used which are:
| Safe working load (SWL) | Proof load |
| Up to and including 3 tonnes | SWL plus 100 per cent |
| Over 3 tonnes, up to and including 6 tonnes | SWL plus 3 tonnes |
| Over 6 tonnes, up to and including 20 tonnes | SWL plus 50 per cent |
| Over 20 tonnes, up to and including 40 tonnes | SWL plus 10 tonnes |
| Over 40 tonnes | SWL plus 25 per cent |
15 When a vacuum lifting attachment is powered by a vacuum pump, the operator and other persons in the vicinity of the lifting operation should be made aware of any failure in the drive to the vacuum pump by audible and visible means.
16 Whenever possible, the vacuum lifting attachment should be fitted with a vacuum reservoir of sufficient capacity to allow the load to be retained for at least five minutes in the event of the failure of the vacuum pump. A suitable warning attachment should be fitted in addition to the reservoir vacuum condition indicator (see para 17), which gives a clearly audible or visible warning to operators and others working in the vicinity when the vacuum in the reservoir is below 80% of the normal working vacuum.
17 Vacuum lifting attachments should be fitted with a large, easily read gauge or gauges which, with the load suspended from the attachment, gives the operator and others in the vicinity of the lifting operation clear indication of the vacuum condition.
18 Any flexible hose or 'wander leads' should be of the armoured type and should be protected as far as possible from accidental damage.
19 It is essential that these attachments should be carefully maintained and subjected to regular inspection and examination:
(1) at the beginning of each shift/day, all pads should be inspected for faults and all warning attachments should be tested;
(2) at weekly intervals the inspection should include pipelines, connections, gauges and filters; and
(3) in line with paras 9-11 above, they should be thoroughly examined by a competent person at appropriate intervals. Where the vacuum lifting attachment is permanently fixed to a crane, gantry or similar, it should be thoroughly examined at 14-monthly intervals. Where it is used in the same manner as a sling or other lifting tackle, ie moved between different lifting machines, then although such devices are not lifting tackle, as defined in law, a suitable interval between thorough examinations will be 6 months.
20 Vacuum lifting equipment is unsuitable for circumstances where the load is likely to pass over personnel or where the sudden fall of the load could have dangerous consequences eg the rupture of steam pipes or other services hit by the falling load.
18 Care should be taken to ensure that the materials lifted are those for which the attachment was designed. Particular care should be taken when handling porous materials, which may impair the lifting capacity of the attachment. Thin sheets of flexible material require careful positioning to avoid peeling away from the pad due to excessive overhang. If necessary a multi-pad attachment should be used. Sliding of inclined sheets across the pads can also occur and unless the attachment is specially designed for the purpose, inclined loads should not be lifted. It is essential to position the pads correctly and it is also essential to wipe all surfaces prior to the lift, as loose materials can cause leaks and have caused loads to drop.