The pre-commission cleaning of hot water heating and chilled systems has become more important over recent years, due to the equipment used being more susceptible to blockages at strainers, control valves and small bore heat exchangers. System contaminants such as millscale, jointing compounds and fabricating debris need to be removed by chemical cleaning and high velocity flushing, which will then allow the on-going water treatment regime to work effectively in preventing corrosion and microbiological fouling. Older systems that have accumulated deposits due to lack of the correct water treatment can be cleaned by a similar method.
Specialist, effective pre-commission cleaning, biocidal flushing and system flushing chemical formulations are available from Water Hygiene Services Ltd.
New installed pipework can frequently have debris, such as millscale from steel pipework, oil and grease and welding and soldering residues contaminating the system. Flushing of the pipework with water alone is not sufficient to remove contaminates which adhere to the surfaces of the pipes. Water Hygiene Services Ltd follows the recommendations of BSRIA, which consists in general of the following steps:
- Inspection of the system and identifying ideal positions for the flushing points, if these have not already been allowed for by the pipework contractor
- Identifying whether the pipework contractor is to carry out the water flush prior to chemical cleaning
- Establishing how the flushing velocities are to be achieved i.e. pumping requirements
- Flushing the system with water at high velocity
- Adding a chemical cleaner to the system water to remove oil, grease, corrosion deposits and to mobilise any suspended solids present.
- Biocidal flushing of the system may also be necessary
- High velocity flushing of individual circuits of the system to achieve the flushing velocities recommended by BSRIA and removing excess chemical cleaner
- Testing the water for the presence of iron and suspended solids etc
- Addition of a corrosion inhibitor for long term protection
- Installation of a side stream hydro-cyclone filter to remove small amounts of suspended solids after commissioning
- Regular service visits to chemically test the water and maintain the correct inhibitor level and to ensure that bacterial levels are within acceptable limits
Existing heating or chilled water systems that are being extended, or may be experiencing poor heat output due to low flow rates, can be chemically cleaned by a similar method. Special precautions should be made to ensure that corrosion products that may be loosened by the cleaning process do not cause blockages. The experience of WHS Group, not only in formulating chemicals for this type of cleaning, but also with our in depth knowledge of the problems encountered, will ensure that our customers receive the correct advice. Please click here to speak to one of our knowledgeable team today.