28 - Before any formal health and safety management system for
water systems can be implemented, a risk assessment has to be
carried out to decide the possible risks. The purpose of the assessment
is to enable a decision to decide:
(a) the risk to health, i.e. whether
the potential for harm to health from exposure is reasonably
foreseeable unless adequate precautionary measures are taken;
(b) the necessary measures to prevent,
or adequately control, the risk from exposure to legionella
bacteria.
29 - The risk assessment also enables the person on whom the
statutory duty falls to show that all the pertinent factors, and
the steps needed to prevent or control the risk, have been considered.
30 - In conducting the assessment, the person on whom the statutory
duty falls needs to have access to competent help and advice.
Further guidance on this is in paragraph 44. This source of advice
may not necessarily be within the person’s organisation
but may be from a consultancy, water treatment company or a person
experienced in carrying out risk assessments. Employers are required
to consult employees or their representatives about the arrangements
for getting competent help and advice (see paragraph 17).
31 - It is the duty of the responsible person (see paragraph
39) to make reasonable enquiries to ensure that organisations
such as water treatment companies or consultants, together with
personnel from the occupier’s organisation, are competent
and suitably trained and have the necessary equipment to carry
out their duties within the written scheme in a safe and adequate
manner. Further guidance on this is in paragraphs 44–46
and 50.
32 - A number of factors are required to create a risk of acquiring
legionellosis, such as:
(a) the presence of legionella bacteria;
(b) conditions suitable for multiplication
of the organisms eg suitable temperature (20°C–45°C)
and a source of nutrients eg sludge, scale, rust, algae and
other organic matter;
(c) a means of creating and disseminating
breathable droplets eg the aerosol generated by a cooling tower
or shower; and
(d) the presence (and numbers) of people
who may be exposed, especially in premises where occupants are
particularly vulnerable, eg healthcare.
33 - While there will inevitably be common factors associated
with the many and varied types of premises being assessed, the
individual nature of each site should be taken into account. In
complex systems or premises, a site survey of all the water systems
should be carried out and should include an asset register of
all associated plant, pumps, strainers and other relevant items.
This should include an up-to-date drawing/diagram showing the
layout of the plant or system, including parts temporarily out
of use. A schematic diagram would be sufficient. It should then
be decided which parts of the water system, for example, which
specific equipment and services, may pose a risk to those at work
or other people.
34 - The following list contains some of the factors which should
be considered, as appropriate, when carrying out the assessment:
(a) the source of system supply water,
for example, whether from a mains supply or not;
(b) possible sources of contamination
of the supply water within the premises before it reaches the
cold water storage cistern, calorifier, cooling tower or any
other system using water that may present a risk of exposure
to legionella bacteria;
(c) the normal plant operating characteristics;
and
(d) unusual, but reasonably foreseeable
operating conditions, for example breakdowns.
35 - Where there is a risk, the significant findings of the assessment
should be recorded (if there are five or more employees). In any
case, it may be necessary to record sufficient details of the
assessment to be able to show that it has been done. The record
of the assessment should be linked to other relevant health and
safety records and, in particular, to the written scheme referred
to in paragraph 53.
36 - Employers are required to consult employees or their representatives
on the identified risks of exposure to legionella bacteria and
on the measures and actions taken to control the risks. The employees
should be given an opportunity to comment on the assessment and
control measures and the employer has to take account of these
views. It is therefore important for employers to publicise to
employees that a legionella risk assessment has been performed
and one means by which employers could ensure that employees are
informed of the measures and actions taken to control risks, and
have an opportunity to comment on the risk assessment, would be
by displaying the appropriate parts of the risk assessment.
37 - It is essential that the effectiveness of the control measures
is monitored and decisions made on the frequency and manner of
this monitoring.
38 - The assessment should be reviewed regularly (at least every
two years) and, whenever there is reason to suspect that it is
no longer valid. An indication of when to review the assessment
and what needs to be reviewed should be recorded. This may result
from, for example:
(a) changes to the water system or its
use;
(b) changes to the use of the building
in which the water system is installed;
(c) the availability of new information
about risks or control measures;
(d) the results of checks indicating
that control measures are no longer effective;
(e) a case of Legionnaires’ disease/legionellosis
is associated with the system.
This document is continued in the next issue of Accepta's newsletter.....
For further information, technical support and advice on all aspects
of Legionella and legislative compliance please call Accepta on
+44 (0) 161 877 2334 or e-mail info@accepta.com.
