Welcome to issue 29; the last one for 2005! Before we get into the detail of this one we'd like to thank you for your loyalty and send our good wishes to you for the festive period and wish you a very successful 2006. You may also like to know that we’ve got a new range of Good Practice Guides for next year that I’m sure will help to add value to your own business offering, so please join us again in 2006.

This month we continue with part 4 of our serialisation of the UK's primary Legionella control document, the Health and Safety Commission’s Approved Code of Practice (ACoP) "Legionnaires' disease: The control of legionella bacteria in water systems" (L8)", with extracts dealing with Legionella risk assessments. We also feature a Good Practice guide concerned with reverse osmosis plant start-up, and discuss the potential global threat of avian influenza or bird flu.

If you find our newsletter useful please pass it on to friends and colleagues. And if there are any subjects you'd like to see included in future issues please e-mail us at subscribe@accepta.com.

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In this issue:

• Part 4- The UK's Approved Code of Practice (ACoP) and Guidance "Legionnaires' disease: The control of legionella bacteria in water systems" (L8).
• Reverse osmosis (RO) plant start-up - a good practice guide.
• Working with avian influenza virus - bird flu.

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Approved Code of Practice Part 4

Approved Code of Practice (ACoP) and Guidance

"Legionnaires' disease: The control of legionella bacteria in water systems" (L8)

Guidance

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, ie 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.

Carrying out a risk assessment

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.

Extracted with permission from "Approved Code of Practice (ACoP) and Guidance "Legionnaires' disease: The control of Legionella bacteria in water systems" (L8)" © Crown copyright

more next time.....

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Reverse Osmosis (RO) Plant Start-Up

Good Practice Guide

Before starting up a reverse osmosis plant system, it should be verified that all pretreatment systems are working according to their specifications. It may be necessary to take water samples for analysis. In the case of polyamide (thin film composite) membranes free chlorine must be 0.0 ppm.

The Silt Density Index (SDI) should be according to the RO design guidelines (typically < 5.0).

If the water analysis (ions, temperature, pH) has changed significantly, it is recommended that you run a new scale projection analysis on Accepta's ROCsoft system.

On startup, the inlet valve should open prior to the initiation of the high-pressure pump, to completely fill the system with low pressure water (<100 psi [< 7 Bars]). This “soft start” will prevent hydraulic shock at startup. Pre-treatment chemical addition should begin at this time (making sure the chemicals are not over-injected). The high-pressure pump should then be started and the system slowly bought on-line, up to design permeate flow.

If starting up after a period of shutdown, flush the permeate to drain for 30 minutes to remove residual preservation chemicals. Produced water permeate can be used when it meets the quality requirement of downstream processes.

For further information or assistance on RO plant installations or specialist supplies please contact us at sales@accepta.com.

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Working with Highly Pathogenic

Avian Influenza Virus

What is Avian Influenza?

Avian influenza, also known as bird flu is a virus that causes disease in birds. Poultry, pigeons and wild or migratory birds, such as ducks, can become infected with the virus. There are two forms of the virus: high pathogenicity (HPAI) and low pathogenicity (LPAI). Pathogenicity indicates the severity of the disease if the bird contracts the virus.

Is it the same as pandemic flu?

No. When the Government refers to Pandemic flu, it is referring to an outbreak of human flu that affects the global human populations. Human Pandemic flu can occur at anytime and does not require exposure to birds.

What is H5N1 and why is it so important?

The Avian influenza A subtype H5N1 is a highly pathogenic (HPAI) strain of the virus that has been confirmed in poultry populations across Asia, Russia and some southern European countries.

Although this is a disease of birds it has been shown in S.E.Asia that it can (although rarely) be transmitted to humans.

H5N1 is also important because it raises the concern that it could recombine with seasonal human influenza virus and create a new and potentially pandemic human flu strain.

I've been to S.E.Asia recently where there are cases of bird flu - what should I do?

If you work with birds in the UK and you have recently visited countries with bird flu, you need to tell your employer. If you feel ill or have any flu-like symptoms within a few weeks of your return, go to your doctor and tell him/her of the country you visited.

I work with birds, can I catch avian flu?

To date, bird to human transmission of H5N1 has been confirmed in a relatively few cases in.....more