AAMI/TIR34 – 2014

What is TIR34?

TIR34 describes two kinds of water, utility water and critical water. Utility water is tap water and may be appropriate for certain parts of the cleaning process. Critical water is treated water (e.g., softened, reverse osmosis, deionized, etc.) used to remove contaminants that may impede critical aspects of processing. In the final rinse, critical water provides better performance in removing residual detergent and impurities from the instruments than utility water. TIR34 establishes maximum levels for water contaminants.

Water treatment can be chemical, filtration, membrane or exchange means. The tables below shows several types of technology for TIR utility quality water as well as maximum acceptable containment levels for critical water.

Water Treatment Technologies to improve utility quality water purity chart

Contaminant Filter Type/Treatment
Particulates/Sediments 0.5 micron particulate filter or smaller
Bacteria 0.2 micron filter
Total Organic Carbon Activated carbon filter
Iron, Manganese Greensand
Copper Cannot be filtered; soften or add RO or DI water to the water supply
Hardness Softener
Endotoxins Ultrafilters
pH Adjustment Chemical feed/adjustment
Chloride Cannot be filtered; add RO or DI water to the water supply to lower the chloride level or use RO or DI water exclusively


TIR34 critical water maximum acceptable contaminant levels chart

Type of Water Utility Water Critical Water
Contaminant Units Specification
Hardness mg/L <150 <1
Conductivity mS/cm <500 <10
pH pH units 6-9 5-7
Chlorides mg/L <250 <1
Iron mg/L <0.2 <0.2
Copper mg/L <0.1 <0.1
Manganese mg/L <0.1 <0.1
Total Organic Carbon mg/L <1.0 <1.0
Bacteria CFU/ml N/A <10
Endotoxin EU/ml N/A <10


Why Comply with TIR34?

TIR34 provides a baseline for water quality that will help to address any water-based issues you may have. If your water supplies comply with AAMI TIR34, you will have fewer complaints and costly rescheduling of surgeries and procedures where instruments were rejected. Money will be saved on detergent because purer water requires less detergent to effectively clean instruments and the water will be less likely to deposit residues on the instruments, thus reducing corrosion, damage and costs.

What is the difference among Standards, Recommended Practices and Technical Information Reports?

Standards and recommended practices are subject to a formal process of committee approval, public review, and resolution of all comments. This process of consensus is supervised by the AAMI (Association for the Advancement of Medical Instrumentation) Standards Board and, in the case of American National Standards, by the American National Standards Institute. A TIR (Technical Information Report) is not subject to the same formal approval process as a standard. However, a TIR is approved for distribution by a technical committee and the AAMI Standards Board.

A TIR is developed because it is more responsive to underlying safety or performance issues than a standard or recommended practice. Other times, a TIR is developed to achieve a consensus that is extremely difficult or unlikely. Unlike a standard, a TIR permits the inclusion of differing viewpoints on technical issues.

Unsure how your water matches up to TIR34? Need consulting to help decide how your water measures up? Call Industrial Water Solutions at 800-820-9021> or send us an e-mail at info@industrialh2osolutions.com.