Chemical indicators for autoclaves and steam sterilizers play a critical role in sterility assurance programs. There are many types of chemical indicators, such as bowie dick test packs and chemical indicator strips. All chemical indicators are designed to respond to physical conditions inside the sterilizing chamber. This validates that an autoclave or steam sterilizer is working properly. It also verifies that it met the conditions for sterilization to occur.

1. Chemical Indicators for Steam Sterilization
6 CLASSIFICATIONS FOR TYPICAL LIFE SCIENCE APPLICATIONS

2. Chemical indicators for autoclaves and steam sterilizers play a critical role in sterility assurance
programs. There are many types of chemical indicators, such as bowie dick test packs and chemical
indicator strips.
All chemical indicators are designed to respond to physical conditions inside the sterilizing chamber.
This validates that an autoclave or steam sterilizer is working properly. It also verifies that it met the
conditions for sterilization to occur.
Chemical Indicators Overview
Overview Standards Classes

3. Standards for Chemical Indicators
The International Organization for Standardization (ISO) issues many standards for sterilization
processes. The most current standard is ISO 11140-1:2005. It defines 6 different classes of chemical
indicators for sterilization.
ISO 11140-1:2005 is identical to:
• BS EN ISO 11140-1:2009
• ANSI/AAMI/ISO 11140-1:2005
ISO 11140-1:2005 replaces
previous standards:
• EN867-1
• ANSI/AAMI ST60:1996
Overview Standards Classes

4. 6 Classes of Chemical Indicators for
Steam Sterilization
ISO 11140-1:2005 classifies chemical indicators for autoclaves and sterilizers as follows:
• Class 1: Process Indicators
• Class 2: Specific-Use Indicators
• Class 3: Single-Variable Indicators
• Class 4: Multi-Variable indicators
• Class 5: Integrating Indicators (Integrators)
• Class 6: Emulating Indicators (Cycle Verification Indicators)
The classes are not ranked by level of importance.
Class 1 is not better than class 6. Each class simply denotes performance characteristics and
intended use of chemical indicators.
Overview Standards Classes

5. ISO 11140-1:2005 section 4.1
"The classification structure used is solely to denote the
characteristics and intended use of each type of indicator
when used as defined by the manufacturer. This
classification has no hierarchical significance."
Overview Standards Classes

6. Since performance requirements are distinct, chemical indicators should only comply with
one class.
The following charts summarize the different classes of chemical indicators.
They also provide examples of applications and STERIS Life Sciences products available for
each class.
Use the charts to help choose the correct chemical indicator for monitoring specific
sterilization processes.
Overview Standards Classes

7. 6 Classes of Chemical Indicators for Steam Sterilization
CLASS 1 CLASS 2 CLASS 3 CLASS 4 CLASS 5 CLASS 6
Process Specific-Use Single-Variable Multi-Variable
Integrating
(Integrators)
Emulating
(Cycle Verification)

8. 6 Classes of Chemical Indicators for Steam Sterilization
What They React ToClass
CLASS 1
Process
One or more
critical variables in
the sterilization
process
What They Indicate
The unit has been
directly exposed
to the
sterilization
process
Application Example
Autoclave tape or
chemical indicator
strips
Located inside or
attached to the
outside of packs
Provide visual
confirmation of
exposure to
sterilization
process
STERIS Life Sciences Products
VERIFY™ Valueline Class 1 EO
Chemical Indicator
(PCC003, PCC004)
VERIFY™ Valueline Class 1 Steam
Chemical Indicator
(PCC009)
Steam Indicator Tape
(260010)
EO Indicator Tape
(410100)

9. 6 Classes of Chemical Indicators for Steam Sterilization
What They React ToClass
CLASS 2
Specific-Use
Defined in relevant
sterilization
standards for
specific test
procedures
What They Indicate
Defined in
relevant
sterilization
standards for
specific test
procedures
Application Example
Bowie-Dick test
packs
Test air removal in
a prevacuum
steam sterilization
cycle
STERIS Life Sciences Products
Steraffirm® Bowie-Dick Test Pack
(EQC003)
VERIFY™ Bowie-Dick Test Packs
(EQC009, EQC010)
Daily Air Removal Test–DART®
(NB113, NB215)
VERIFY™ Bowie-Dick Test Card
(S3095)

10. 6 Classes of Chemical Indicators for Steam Sterilization
What They React ToClass
CLASS 3
Single-
Variable
One critical
variable in the
sterilization
process
What They Indicate
Exposure to a
sterilization
process at a
stated value (SV)
of the variable
Application Example
Chemical pellet
Melts at a specified
temperature
Demonstrates the
steam sterilization
process has
achieved a
specified
temperature
STERIS Life Sciences Products
Not currently available

11. 6 Classes of Chemical Indicators for Steam Sterilization
What They React ToClass
CLASS 4
Multi-Variable
Two or more
critical variables in
the sterilization
process
What They Indicate
Exposure to a
sterilization cycle
at stated values
(SVs) of the
variables
Application Example
Chemical indicator
tubes
Change color only
when exposed to a
given temperature
for a specified time
in a steam
sterilization
application
STERIS Life Sciences Products
Steraffirm™ Sterilizer Control Tube
Steam at 121°C/250°F for:
-15 minutes (PCC024)
-12 minutes (PCC025)

12. 6 Classes of Chemical Indicators for Steam Sterilization
What They React ToClass
CLASS 5
Integrating
(Integrators)
All critical variables
in the sterilization
process
What They Indicate
Stated values
(SVs) meet or
exceed
performance
requirements in
the ISO 11138
series for
biological
indicators
Application Example
Moving front
indicators
Respond to all
critical process
parameters
STERIS Life Sciences Products
VERIFY™ Integrating Sterilization
Test Integrator for Moving Front
Steam
(PCC039)

13. 6 Classes of Chemical Indicators for Steam Sterilization
What They React ToClass
CLASS 6
Emulating
(Cycle
Verification)
All critical variables
for specified
sterilization cycles
What They Indicate
Stated values
(SVs) are
generated from
the critical
variables of the
specified
sterilization
process
Application Example
Cycle-specific
indicators
Typically placed in
the pack, pouch or
container
Respond to all
critical process
parameters for a
specified
sterilization cycle
STERIS Life Sciences Products
See next slide

14. 6 Classes of Chemical Indicators for Steam Sterilization
STERIS Life Sciences ProductsClass
CLASS 6
Emulating
(Cycle
Verification)
Steraffirm™ Sterilizer Control Tube
Dry heat at 160°C/320°F for:
-60 minutes (PCC027)
-120 minutes (PCC028)
Steraffirm™ Steam Class 6 Emulating Indicators
-121°C/250°F for 15 minutes (PCC012)
VERIFY™ SixCess® Class 6 Chemical Indicator Strips
Programmed sterilization cycles at:
-121°C/250°F for 30 minutes gravity (PCC005, PCC007)
-132°C/270°F for 15 minutes gravity (PCC031)
-135°C/275°F for three minutes prevacuum (PCC034, PCC038)
-132°C/270°F for four minutes dynamic air removal (PCC006, PCC008)
-135°C/275°F for 10 minutes gravity (PCC033, PCC037)