HTM WATER REGULATIONS
Healthcare Technical Memorandum (HTM)
The healthcare technical memorandum (HTM) provides guidance on disinfection processes. Specifically it refers to the validation of all types of ultrasonic cleaner and washer disinfector used in the healthcare sector. HTM provides guidance on contamination within steam supply, and also defines the specifications for ‘clean steam’ used within the healthcare sector.
HTM defines microbiological specifications that washer disinfectors must meet to ensure patient safety. The final rinse water after the disinfection stage has occurred, must meet quality standards to minimize microbial contamination of disinfected products.
It is recommended that this monitoring be performed on a weekly basis.
Specification for Endoscopy
Initial flush:- Hardness less than 200 mg/L CaCO3
Intermediate flush:- Hardness less than 200 mg/L CaCO3
Water for diluting disinfectants and detergents:- Hardness less than 50 mg/L CaCO3
Final rinse-water(see also Table 1 in HTM01-06 Part E – ‘Testing methods’)
Water hardness less than 50 mg/L CaCO3
TOC less than 1 mg/L
Conductivity less than 40 µS/cm, unless disinfectant added
Note: If any of the above parameters for the final rinse-water are above the stated limits, additional water analysis will be required to determine the source of the problem (for example, pH, chloride, heavy metals etc).
The criteria and parameter limitations for other contaminants including salts not listed in this Table should accord with the rolling revision of the WHO guidelines for drinking water quality.
In light of the use of variable supply quality through the recently established national water grid, it is appropriate for providers to periodically discuss this issue with their water supplier.
Tests for hardness and electrical conductivity are detailed in HTM 01-06 Part E – ‘Testing methods’.
|Water test||Satisfactory results||Frequency|
|Total organic carbon||Less than 1 mg/l||Yearly|
|Appearance)||Clear,bright and colourless||Yearly|
|pH||5.5 to 8.0||Yearly|
|Electrical Conductivity||Less than 40 µS/cm at 25°C||Weekly|
|Hardness||Less than 50 mg/l CaCO3||Weekly (if appropriate)|
|Total viable count (TVC)||Less than 10 cfu/100ml acceptable||Weekly|
|Enviromental mycobacteria||Non-detected in 100 ml samples||Quarterly|
|Pseudomonas aeruginosa||Non-detected in 100 ml samples||Quarterly|
Specification for Sterile Services
Cold water:- Flushing
Potable water:- Flushing/washing
Soft potable water (<50mg/L / CaCO3):- Cleaning with detergent or enzymatic cleaners
Softened water-based exchange softener:- Desirable in all water >50mg/L/ CaCO3 Essential in all water >125mg/L / CaCO3 for use in WDs
Deionised water:- Final rinse water in all WDs Thermal disinfection in all WDs
Reverse osmosis:- Final rinse water in all WDs Thermal disinfection in all WDs
Note:- This table shows suitable applications for the various qualities of water commonly available.
Although water of lower quality may be used, this will normally require additional chemical additives and might entail some impairment of the WD performance. The terms “softened”, “deionised” and “reverse osmosis” refer to defined purification processes.
|Determinant and unit||Maximum permitted values|
|Final rinse||Other stages|
|Degree of acidity(pH)||5.5 to 8.0||–|
|Conductivity at 25°C (µS/cm)||30||–|
|Total dissolved solids (mg/100ml)||4||–|
|Total hardness CaCO3 (mg/100ml)||50||210|
|Heavy Metals, determined as Lead, Pb(mg/l)||10||–|
|Iron, Fe (mg/l)||2||–|
|Phosphate, P2O5 (mg/l)||0.2||–|
|Sillicate, SiO2 (mg/l)||0.2||2|
|Total viable count (TVC) at 22°C (cfu/100ml)||100||–|
|Total viable count (TVC) at 37°C (cfu/100ml)||100||–|
|Bacterial endotoxins (EU/ml)||0.25||–|