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For any one using a class 3b or class
4 laser, a risk assessment and local rules must be in place before the laser
is switched on. Once a risk assessment and local rules have been approved
by the laser safety officer within the Engineering Department (Dr Tim Wilkinson),
then the laser can be used. A copy of the risk assessment and local rules
must be kept on site with the laser(s) being assessed. These documents can
be requested for inspection at any time.
The purpose of the risk assessment
is to identify potential hazards within an experiment and put in place as
many safety controls to minimise those hazards where practicable. These controls
can vary from physical barriers to training and procedural awareness.
The risk assessment is expressed
through the NRPB format laser risk assessment
form. This is designed to set out the risk assessment into 4 logical stages.
The laser itself, the beam delivery system, the experimental system and the
environment. Each of these are expressed on a separate page of the risk assessment
form. Your particular system may not need all 4 sections, hence some pages
may be blank or refer to others.
Each of the 4 sections has been set
out to list the hazard, the person(s) at risk, the control measures and the
actions (if required). The action section (second page) is there in case further
work is needed to control a particular hazard. Any outstanding actions should
be accompanied by a rough estimate of the date of completion. There is also
an extra sheet for each section of the form to allow more detailed actions
to be specified and administered.
The 4 main sections are set out as
follows:
· The laser. This section covers everything that might
be a hazard BEFORE the laser actually emits light. This includes potential
hazards such as electrocution from high voltage power supplies, flooding due
to water based chilling systems, hazardous chemicals such as dyes which may
be contained within the laser or even possibly the size and weight of the
laser itself crushing someone (or their foot!). Typical control mechanisms
will include the type of box the laser is in, how (and by whom) is it maintained,
plumbed in etc.
· The Beam Delivery. This section covers the way in which the
beam gets from the laser to the experimental setup. This is often a very important
section, especially if the beam is propagating in free-space as this must
be very carefully justified and assessed under the latest
What sort of controls will you put
in place to avoid these hazards? The best is always to enclose the beam as
much as possible. This is always the recommended course of action, however
there are always extreme cases where enclosure is not possible. YOU MUST EXPLICITELY
SAY WHY IN YOUR RISK ASSESSMENT. Other control mechanisms include sensible
layout of components, alignment at reduced (specified) power levels, training,
operating procedures and as a last defence mechanism, personal protective
equipment (
· The Environment. This section covers
the location of the laser and experiment. Those at risk might be the users
or possibly others who might use the lab or stumble in by accident. Where
is the system located? Who else has access? How is access to the laser/lab
controlled? Are there keys, codes or cards? Who has them? Are there interlocks
in place to prevent exposure if the box or lab is opened unexpectedly? Is
the signage suitable to warn others in the lab?
The second part of the risk assessment process is to produce a set of local rules for safe operation. This is a compulsory part of the risk assessment process and should contain the following information:
The local rules summarise the key points from the risk assessment as well as outline any detailed procedures which must be used to operate or align a laser based experiment or system. They should also contain useful details and contacts should a hazardous incident occur.
A pro-forma set of local rules are shown here. A fully completed set for a typical PIV system are shown here.
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Last content change : Jan 21