This presentation looks at superheat in porous load autoclaves. It explains what superheat is, why superheat is a problem and identifies the causes superheat.
3. WhyisSuperheat aProblem?
Moist heat is a very effective method of kill, almost 5 times faster than dry heat.
Moist heat delivers rapid heat transfer, breaking
down cell walls.
Superheated steam demonstrates a lack of
moisture, which can impact the ability to break
down the cell walls.
4. Autoclave
Basic overview of how a Porous Load Steam Steriliser works
Steam pressure is controlled to ensure
the drain is the correct temperature.
Baffle plates force steam to displace
air, down the drain.
Jacket Surrounding Chamber
5. Potential Causes
Superheat can be caused by several factors:
Steam Distribution / Steam Quality Issues
• Steam Generator Issues
Autoclave
• Jacket Temperature Higher than autoclave
control setpoint
Load Design and Preparation
• Load Item Materials of Construction
• Paper, goggles, mops etc.
• Load Wrapping Materials
6. Potential Causes
Steam Distribution / Steam Quality
Step 1
Perform Steam Quality Testing (EN285:2015, PDA Technical Report 1)
• At Point of Use
• At Point of Generation
Step 2
Perform a Distribution Survey
• Check Steam Traps
• Pipe levels etc
7. Potential Causes
Load Items
Some load Items are known to absorb moisture
from steam, generating localised superheat
including:
Goggles Paper Clean Room Garments
8. Potential Causes
Autoclave
The Jacket temperature should be below
sterilisation temperature. To allow
condensate to form and go to drain.
If the jacket temperature is higher than
the control temperature, it may create
localised superheat.
Adiabatic Expansion
Steam entering the chamber
through a small orifice, when it
expands the temperature
increases.
9. 0201
ABOUT US
We deliver practical validation
training courses in:
• Autoclave Validation
• Temperature Mapping
• Steam Quality Testing
• Kaye Validator 2000
Training
We can help with:
• Wet Loads
• Superheat Investigations
• Equilibration Failures
• Steam Quality Failures
• Biological Indicator Failures
Consultancy 03We perform Validation on a
wide range of equipment:
• LN2 Freezers – Ovens
• Autoclaves and SIP
• Freeze Driers
• Dry Heat Processes
Validation
10. CONTACT US
www.thermalcompliance.co.uk
18 Harelands Courtyard Offices
Moor Road Melsonby
Richmond
DL10 5NY
UK
Tel +44 (0)1748 327 247
www.thermalcompliance.com
Chris Maughan
Managing Director
Thermal Compliance
chrism@thermalcompliance.co.uk
