Prior to the publication of AAMI’s Technical Information Report 34:2014 Revision 2017 (TIR34), there was very little guidance on the monitoring of waters used for rinsing in washer or washers/disinfectors used to clean and sterilize reprocessed medical devices. TIR34 not only outlines water quality requirements for these waters, but also contains suggested frequencies and locations for water treatment equipment, storage tanks, and distribution equipment.
Critical vs. Utility Water
There are two classifications of water defined in TIR34; Critical Water and Utility Water. Tap water or potable water is often suitable for Utility Water which may be used for general washing applications, initial rinsing, or cleaning and rinsing of non-critical instruments and devices. Certain feed waters may require modest treatment to meet the specifications defined for Utility Water. Critical Water, however, is defined by specific quality attributes including tight specifications for bacteria and endotoxin of 10 cfu/ml and 10 Eu/ml respectively. Critical Water applications include cleaning and rinsing of critical devices and water for steam sterilization. It is ultimately the responsibility of the end-user to determine the appropriate quality of water required for the application.
Critical Water applications include cleaning and rinsing of critical devices and water for steam sterilization.
Annex B of TIR34 offers a guideline for monitoring of water treatment systems and final water quality for water used for reprocessing equipment. Although no differentiation is made for Utility versus Critical Water, the guidance is assumed to be based on Critical Water Systems. For general device reprocessing areas, a frequency of - no less - than once per quarter is recommended. This is generally recognized as the minimum amount of water quality sampling required at use-points or in the distribution loop required to maintain compliance with TIR34.
To maintain compliance with TIR34 - it is ultimately the responsibility of the end-user to determine the appropriate quality of water required for the application.
Establishing a Monitoring Plan
There are guidelines for monitoring the performance of specific water treatment unit operations outlined in TIR34 as well. Generally, the recommendations are for daily monitoring of treatment processes based on manufacturer’s recommendations. This is typical of most water treatment systems where daily monitoring is used to accumulate operating data and establish maintenance frequencies. The data can be accumulated via on-line data acquisition systems or, more commonly for healthcare systems, it is recorded by facilities personnel or on-staff technicians. The parameters monitored should be based on the function of each unit operation in the system. For instance, the function of a water softener is to remove or reduce the hardness levels in the feed water. A monitoring plan for a softener should include effluent hardness monitoring to ensure the softener is working properly.
By its very definition and application, monitoring of Critical Water Systems should be more intense than Utility Water Systems, which likely contain fewer, if any, treatment techniques.Water quality requirements for Critical Water Systems that include bacteria and endotoxin specification are affected by the operation and maintenance of water treatment components, it is important that they are monitored throughout the entire system and not just at the use-points. The acquired data can be used to establish changeout frequencies of microbial control techniques such as submicron filters, UV lights, and ultrafilters, as well as sanitization frequencies for the system. Manufacturer’s instructions for use should also be considered when establishing maintenance intervals.
It is recommended that an intense initial monitoring plan be initiated after system commissioning to establish the frequencies. Maintenance should be performed on a preventive basis before any system upsets are identified. This is consistent with TIR 34 which suggests an initial testing interval of one week until a pattern of consistent compliance can be demonstrated. During this period, it is suggested that daily sampling of the use points be staggered while still sampling each point at least once per week.
Maintenance should be performed on a preventive basis before any system upsets are identified.
The data should be recorded and trended. From the data, we can not only verify maintenance intervals, but identify any seasonal fluctuations and identify excursions from standard deviations to implement corrective techniques before the quality specifications are exceeded. Additional quality control techniques should include inspection of devices, washers and sterilizers for any indications of impurities from the water.
Summary of Recommendations
The following is a summary of our recommendations for water quality monitoring plans for systems to meet AAMI TIR34: 2014(R)2017 standards.
Critical Water Systems should be monitored more closely than Utility Water Systems
Routine operating data for generation system should be recorded daily
Bacteria and endotoxin samples should be taken at least once per month at use-points
Microbial sampling should include points in the generation system to ensure the system is operating in a state of control
More robust microbial sampling should be performed initially after system commissioning to establish a baseline for maintenance frequencies
All data should be recorded, trended, and analyzed. Continuous improvements and system or procedural enhancements are encouraged.