APPENDIX D: Safe Maintenance, Repair and Cleaning Procedures

Safe Maintenance, Repair and Cleaning Procedures

Introduction

The following provides guidance on the key areas employers need to address in order to meet the requirements of DSEAR and covers the need to identify hazards and implement appropriate control measures and systems of work during maintenance and other similar non-routine activities. It includes guidance on hot work and permit to work systems for those activities identified as high risk.

Assessment of the risk

Employers must carry out a risk assessment before:

any maintenance, repair, extension, restructuring, demolition or cleaning activities are undertaken in areas, or on any plant where dangerous substances are used, stored or produced
using a dangerous substance for any maintenance, repair or cleaning

The factors the employer should consider in the assessment when undertaking maintenance, repair or cleaning activities include:

materials that are or have been used in the area or plant where the activity is to be undertaken
dangerous materials that may become hazardous under the activity to be undertaken
potential heat or ignition sources that may be present during the work activity
explosive atmospheres; where and how they can arise
fire and explosion consequences
maintaining safety during the work activity, e.g. removal of dangerous substances, isolating pipe work
training and competency levels of operatives
requirement of any additional protective and emergency equipment
systems of work to implement necessary control measures

Where it is not practicable to remove the dangerous substance from the work area during maintenance, repair or cleaning activities the employer should take the necessary measures identified by the assessment to control the risks from fire or explosion. These will include:

minimising the presence and avoiding release of dangerous substances
preventing an explosive atmosphere by adequate ventilation or inerting
preventing ignition sources being brought in to the work area
providing appropriate emergency arrangements and equipment

Dangerous substances used as cleaning agents

Use of dangerous substances for cleaning purposes should be avoided wherever possible and less hazardous substance used where possible. For manual cleaning operations the use of a dangerous substance should be minimised by:

applying it to a surface in small sections
providing adequate ventilation
ensuring ignition sources are eliminated
ensuring appropriate dispensing containers are used
ensuring the cleaning substance is compatible with other dangerous substances present

Operating procedures

For low risk activities such as routine cleaning operations, dealing with small leaks and spills during normal operations, and routine machine and equipment adjustments, the employer should ensure that:

risks are identified before work commences and where necessary incorporate control measures in to written operating procedures
control measures are implemented through adequate supervision or system of work
activities do not increase the level of risk with the normal work activities, e.g. introduce ignition sources

For medium risk activities such as maintenance, repairs, servicing, leak testing of tanks and lines, hot work in areas where there are only small quantities of dangerous substances, the employer should ensure that appropriate control measures are implemented through the use of safety method statements.

A safety method statement is a written procedure to cover a particular non-routine task. As well as specifying the work to be done it will identify the hazards and the necessary control measures. Safety method statements are inappropriate for highrisk activities, which should be subject to a permit to work system but safety method statements may be incorporated into the permit to work system. The safety method statement should be clear and concise and contain the following information:

A description of the task and where it is to be undertaken
Sequence and method of work
Hazards identified during the risk assessment
Skills required to deal with the hazards
Precautions necessary to control the hazards
References to specific safety procedures covering known hazards
Details of any isolations and any related control procedures
Details of tools and equipment to be used
Method of disposal of waste and debris
Details in which the plant or equipment will be left in at the end of the activity

For high risk activities such as hot work on any plant or equipment remaining in situ that contains or may have contained a dangerous substance, hot work or introducing ignition sources in areas that are classified as hazardous under these Regulations, hot work in the vicinity of plant or equipment containing a dangerous substance where a fire outbreak could spread to them, working in a confined space which contains or has contained a dangerous substance, or opening or breaking into plant or equipment.

Hot work is considered to be any procedure which may involve or have the potential to generate sufficient heat, sparks or flames to cause a fire and includes welding, flame cutting, soldering brazing, grinding, using disc cutters and other similar equipment.

For high risk activities the employer should ensure that a permit to work is in operation. A permit to work procedure is a documented system that authorises certain personnel to undertake specific work within a specified time frame. The permit to work will describe the precautions required to complete the work safely and the employer should ensure that:

the permit to work is only issued by a responsible competent person
all those involved in the permit to work system are aware and understand their responsibilities and duties
those issuing, monitoring and auditing the permits are trained to do so
the system is audited and monitored to ensure that it works

If a permit to work system operated by site personnel is required to be used by a contractor, sub-contractor or self-employed, the employer of the contracting company should ensure employees and supervisors are made aware of their responsibilities and duties under the system and are made aware of any procedures or special arrangements in place for a job, area or location in which they are to work.

Wherever possible the need for hot should be eliminated by the use of other processes that do not need the application of heat or the generation of heat or sparks.

The employer should ensure, where reasonably practicable, that before any hot work is undertaken:

cleaning is undertaken by a competent person to eliminate the presence of any dangerous substance
plant or equipment is isolated from all sources of dangerous substance and ventilated to remove flammable vapours
the atmosphere inside the plant or equipment is monitored by a competent person before any hot work commences and throughout the work activity to ensure that the concentration of any dangerous substance is less that 1% of the lower explosion limit
risk assessments and appropriate safety procedures have been undertaken and implemented before any isolating, cleaning and gas freeing of plant and equipment commences

Where it is not reasonably practicable to eliminate dangerous substances by adequate cleaning methods then the employer must implement measures to control the fire and explosion risk arising from hot work activity.

Other methods of eliminating dangerous substances can be used such as inerting and this can be applied where plant and equipment has been emptied of the dangerous substance or it is impracticable to clean the plant adequately.

Inerting methods may use the water, nitrogen foam, nitrogen gas, combustion gas, or carbon dioxide. Inerting methods are only applicable to dangerous substances that are flammable, highly flammable, extremely flammable, or an explosion hazard on heating. Inerting methods are not applicable to dangerous substances that are oxidising material or chemically unstable

Before commencing work on plant or equipment that has been inerted with an inert material the atmosphere should be checked at various levels using a calibrated oxygen meter to ensure the oxygen content has been reduced to below the required level.

Working on live plant

In exceptional circumstances hot work can be undertaken on plant or equipment containing a dangerous substance without cleaning or inerting. Such methods are only applicable to plant or equipment containing a liquid or gases. Where hot work is to be undertaken on plant or equipment that still contains a dangerous substance the employer must ensure that:

an explosive atmosphere cannot be formed by preventing air or oxygen entering
flames or heat will only be applied to the outside surface of the plant
the plant cannot fail or leak and allow the liquid or gas to escape and ignite as a result of the hot work activity
the composition of the gas or liquid cannot alter to become an explosive atmosphere
movement of materials can be controlled in or out of the plant and associated plant or equipment
substances or residues present cannot undergo any reaction or decomposition
a permit to work system is implemented
all personnel involved in the work activity are competent and trained

there are no explosive atmospheres around the work area arising from the plant being worked or other work activities

Gas welding and cutting equipment

The gaseous fuels and oxygen used in gas welding and cutting equipment are classed as dangerous substances and subject to DSEAR and employers are required to assess the risks arising from their use and implement appropriate control measures.