Safety alert - Operation of auger feed devices

Safety Alert: ESA 1/2009

Issue date:  January 2009

Introduction

The Health and Safety Executive was recently informed of a serious accident which occurred while an operator was working on a Mobile Explosives Manufacturing Unit.

The operator sustained serious hand injuries while clearing a blockage in an auger feed device.

The circumstances of the accident have prompted HSE to issue the following safety advice to companies that operate Manufacturing Units equipped with auger feed devices.

Background

A Mobile Explosives Manufacturing Unit (MEMU) is used for the on-site mixing of blasting explosive. The MEMU is a road-going vehicle fitted with tanks to hold materials (emulsion phase and a solid constituent) which, when mixed and sensitised, produce a blasting explosive.

An operator was filling his Mobile Explosives Manufacturing Unit (MEMU) with emulsion phase (EP) from an external tank, using an external Bowie pump. The pump was driven by the auxiliary hydraulic system of the vehicle, which requires the engine of the vehicle, on which the MEMU is installed, to be switched on, and a power take-off shaft to be engaged.

The hydraulic fluid was diverted to drive the external pump via a 2-position valve. In this configuration the auger feed device of the Unit should not function.

Whilst filling was taking place, the operator was clearing solid material from the vertical auger feed of the MEMU. This had accumulated and caused a blockage in the feed of the solid constituent. While the operator was attempting to free the blockage, the auger started to turn, causing serious injury.

Action required

Employers should apply a hierarchy of protection measures, where practicable, to the auger systems, as follows:

1. Fixed enclosed guards.
2. Other guards or protection devices, such as interlocked guards, which shut off the drive mechanism if the guard is removed/opened.

Employers should also ensure the provision of such information, instruction, training and supervision as is necessary. Access should only be gained after applying a suitable lock-off procedure/safe system of work.

They should also ensure that any valves in the hydraulic system, used to drive the augers, are suitable for their intended purpose and are maintained to ensure proper functioning. If they are used to divert hydraulic fluid to drive different parts of the machinery, ideally, they should be of a three position type with centre blocking to prevent the potential splitting of pressurised hydraulic fluid.

Employers should have systems in place to ensure that all guards and associated safety devices on MEMUs are regularly checked for defects that may affect correct functioning. The system in place should ensure that if any defects are found they are rectified or the MEMU taken out of use pending rectification.

Relevant legal documents

• Health and Safety at Work etc Act 1974 (HSWA) Section 2(1) - It shall be the duty of every employer to ensure, so far as is reasonably practicable, the health, safety and welfare at work of all his employees.
• HSWA Section 2(2)(a) - Employers to provide and maintain systems of work that are, so far as is reasonably practicable, safe and without risks to health.
• HSWA Section 2(2)(c) – Employers to provide such information, instruction, training and supervision as is necessary to ensure, so far as is reasonably practicable, the health and safety at work of his employees.
• Management of Health and Safety at Work Regulations 1999 (MHSWR), Regulation 3 – Every employer shall make a suitable and sufficient assessment of the risks to the health and safety of his employees to which they are exposed whilst they are at work.
• MHSWR Regulation 13 – Every employer shall ensure that his employees are provided with adequate health and safety training on their being exposed to new or increased risks because of a change respecting work equipment already in use within the employer’s undertaking. The training shall be repeated periodically where appropriate; be adapted to take account of any new or changed risks to the health and safety of the employees concerned.
• Provision and Use of Work Equipment Regulations 1998 (PUWER) Regulation 4 – Every employer shall ensure that work equipment is used only for operations for which, and under conditions for which, it is suitable.
• PUWER Regulation 5 – Every employer shall ensure that work equipment is maintained in an efficient state, in efficient working order and in good repair.
  
  Every employer shall ensure that where any machinery has a maintenance log, the log is kept up to date.
• PUWER Regulation 6 – Every employer shall ensure that work equipment exposed to conditions causing deterioration which is likely to result in dangerous situations is inspected – at suitable intervals; and each time that exceptional circumstances which are liable to jeopardize the safety of the work equipment have occurred, to ensure that health and safety conditions are maintained and that any deterioration can be detected and remedied in good time.
• PUWER Regulation 9 – Every employer shall ensure that all persons who use work equipment have received adequate training for purposes of health and safety, including training in the methods which may be adopted when using the work equipment, any risks which such use may entail and precautions to be taken.
• PUWER Regulation 11 – Every employer shall ensure that measures are taken which are effective – (a) to prevent access to any dangerous part of machinery or to any rotating stock bar; or (b) to stop the movement of any dangerous part of machinery or rotating stock bar before any part of a person enters a danger zone.

References

• FEEM (Federation of European Explosives Manufacturers) Code of Good Practice - Standards for the transport, storage, mixing and handling of bulk emulsion explosives and their components.

Further information

Health and Safety Executive
HID SI2A, Explosives Inspectorate
1.2 Redgrave Court
Bootle, L20 3RA 
Tel: 0151 951 4025
Fax: 0151 951 3891
Website: http://www.hse.gov.uk/explosives/index.htm

General note

All dangerous parts of machinery should be adequately guarded to prevent access to moving parts such as auger feed devices. If, as part of the operation of a MEMU, it is necessary to remove a guard for cleaning or to clear blockage, suitable protection devices should be provided to prevent access to moving parts of machinery.

Access to moving parts of machinery can result in very serious injuries.

Failure to control a risk of serious personal injury may result in the issue of a Prohibition Notice to prohibit the use of the device/equipment until remedial measures are taken.

An Improvement Notice may also be issued if there are breaches of the legislative requirements.

Breaches may result in prosecution.

Please pass this information to colleagues who may have this product/ equipment or operate this type of system/process.

This guidance is issued by the Health and Safety Executive. Following the guidance is not compulsory and you are free to take other action. But if you do follow the guidance you will normally be doing enough to comply with the law. Health and safety inspectors seek to secure compliance with the law and may refer to this guidance as illustrating good practice.