The Ingenieur Vol 57 January-March 2014 The Ingenieur Vol 57 January-March 2014 | страница 48

INGENIEUR Table D: Checklist for Hot and Cold Water Services Service Task Frequency Hot water services Arrange for samples to be taken from hot water calorifiers, in order to note condition of drain water Annually Check temperatures in flow and return at calorifiers Monthly Check water temperature up to one minute to see if it has reached 50°C in the sentinel taps Monthly Visual check on internal surfaces of calorifiers for scale and sludge. Check representative taps for temperature as above on a rotational basis Annually Check tank water temperature remote from ball valve and mains temperature at ball valve. Note maximum temperatures recorded by fixed max/min thermometers where fitted Six monthly Check that temperature is below 25°C after running the water for up to two minutes in the sentinel taps Monthly Visually inspect cold water storage tanks and carry out remedial work where necessary. Check representative taps for temperature as above on a rotational basis Annually Shower heads Dismantle, clean and de-scale shower heads and hoses Quarterly or as necessary Little-used outlets Flush through and purge to drain, or purge to drain immediately before use, without release of aerosols Weekly Cold water services CONCLUSION Anyone involved in the supply of water systems (e.g. designers, manufacturer, vendors, contractors, operators) has the duty, as far as reasonably applicable, to ensure that the water system is designed and constructed so that it is safe when in use and enables safe and easy operation, cleaning and maintenance. Some key points to consider in the design and construction of water systems (cooling, hot and cold water) would be; • Comply with relevant MS or where not available, the appropriate International standards; • Control the release of drift by fitting effective drift eliminators (such devices do not eliminate but rather reduce drift). Spray from other parts of the system should also be controlled; 6 46 VOL 57 JANUARY-MARCH 2014 VOL 55 JUNE 2013 • Aid safe operation – e.g. water circuitry should be as simple as possible, ideally without dead legs, or at least with the length of dead legs limited; • Aid cleaning and disinfection – e.g. those parts of the system which need regular cleaning should be easily accessible, readily removable and easily dismantled; and • Be made of materials which can easily be disinfected and which do not support microbial growth. REFERENCES HSE UK, Legionnaires; disease – Approved Code of Practice & Guidance HPAC Engineering Dec 2009 issue – Greening your Cooling Tower www.legionella.org