The Hierarchy of Control
Most of us like to feel that we have some sort of control in any given situation. Insurance, business contracts, security systems, data protection and risk management are controls we rely on as a part of normal life. They keep us calm and help us sleep.
A useful way of managing risks and maintaining control is to sort the different items that need to be considered into some sort of order of importance (hierarchy of control). This action list helps us set priorities. Those of us who are familiar with Safe Working Environmental Method Statements will be quite familiar with hierarchies of control.
It is worth spending a little bit of time to consider the controls you have in place and their relative importance in a building water system. The principles are the same as they are for any other system, they just need a bit of tweaking.
History
The Hierarchy of Control is not a new concept. It was first developed in the 1940's and 50's when manufacture was booming globally. In the 1960's NASA built it into their race to the moon - along with other useful things like Velcro, dust-busters and HACCP!
The idea is simple. Identify what you CAN do at each step and eliminate what you can't. To make things easy the chart below lists a hierarchy of control for health risks from water systems.
Next it is just a matter of working through what can be done at each level to get the best control possible. The end result is an action plan for managing your risks. The plan also identifies for you what you CAN do, and what you're going to have to put up with (manage).
Elimination of the Organism
OK. This will be very brief. Eliminating the organism (Legionella, Pseudomonas, Mycobacteria - whatever) is not possible in a building water system. Repeat: not possible, cannot be done, unachievable. If someone tells you they can do it ... get a copy of their insurances!
Check out the triangle above - looks fine but won't work in reality! This is where fantasy meets reality. So let's move on....
Replacement of environments conducive to growth
This is quite broad but here's some things to think about. Do you need a cold water storage? Materials of construction particularly plastics / rubbers can be an issue. Flow restrictors and aerators can be removed or replaced. Boil /Chill units and hallway basins are often provided in excess of requirements and very often under-used.
Most environments conducive to growth are associated with stagnation. It is a bad idea to install anything that will not have water flow through it regularly and routinely. Often they don't need replacing they just need removing.
Having accurate drawings can help you quickly spot dead legs, blind ends and the like.
Engineering an environment hostile to growth
This is a follow on from the section above. Once you have removed places that are conducive to growth - make what's left uncomfortable for your unwelcome guests. These are things that can be done before disinfection is even considered. Mostly they are about maintenance.
keep water moving (flush)
service essential equipment (TMV's if they're installed)
flush and clean outlets - remove and clean aerators (like the one below!)
maintain your target temperatures - hot water hot and cold water cold
The aerator above (from an aged care facility) looks like it was specifically designed to collect debris!
Administrative Controls
A simple rule in this is 'if it isn't documented - it didn't happen'. All of the above MUST be documented. The documents will be the only proof you have of an operational plan for managing your risks. This is the first step in administrative control. The second step is keeping the document 'live'. A shiny folder on your shelf somewhere is pretty much useless - and can end up as proof of negligence. Timely reporting and communication are where the rubber meets the road in any control strategy.
Disinfection
Generally disinfection is the last resort unless you are housing or caring for those who are at high risk of infection. Don't go there until you've had a good go at the levels further up the hierarchy. In reality it is likely to be something you have to consider. It may be periodic (every 3 or 6 months) or continuous, if not controllable. There are a multitude of options and these are dealt with on another page!
The bottom line is that if you have Legionella contamination in your system then disinfection is probably unavoidable and may also be a requirement in your jurisdiction. It will go a whole heap better if you've taken some time on the upper levels of the hierarchy!
Reduce Human Exposure at Outlets
Well, mostly, doing all the things we've run through above will do this. Here's some suggestions: Within the bounds of good hygiene and infection control remove as many outlets as possible. It is a good idea to make sure there is good ventilation (ceiling extraction fans) so aerosols do not linger or travel. Avoid the potential for cross contamination of outlets (shower hoses reach toilet basins etc). Leave fans on in bathrooms for a couple of minutes after flushing outlets. Only use garden spray irrigation when either, windows are closed, or people are not around (night time). A good risk management plan will help you spot all sorts of opportunities that are cheap, easy, and effective.
The health and well-being of your staff and co-workers can be easily overlooked. Use of suitable PPE by staff is a no-brainer! But don't forget about education. The success of your management plan hinges on staff understanding the system, the risks and the goals.
All of the mentioned areas above are what we specialize in, our business delivers industry leading processes, systems, training and support as well as market leading disinfection products that will enable you to manage and reduce risk of waterborne infection. We are an ISO accredited business and hold Systems, Safety and Environmental certification, please feel free to contact us if you would like to talk more.
More info?
World Health Organisation 2007. Chapter 3. Approaches to Risk Management.
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