SteriSet containers are CE-marked to demonstrate that they fulfill the general requirements of the European Medical Device Directive. Part of the documentation which was collected for this CE-mark are reports of tests performed according EN 868 part 8 “reusable sterilization containers for steam sterilization”:

Annex E “Determination of sterilization performance”

1. with full standardized metal load

2. with fabric load

Annex F “Load dryness tests”

1. with full standardized metal load

2. with fabric load

Historical evidence over the past 30 years with different vacuum steam cycles acc. (old) German standard DIN 58946 “steam sterilizers” do also propose a very high level of confidence that sterility will be reached during a vacuum steam cycle, provided the cycle is operated within his intended limits.  

In the US, AMSCO American Sterilizer Company did comprehensive  studies on SteriSet's compatibility with AMSCO's US typical steam sterilization cycles for the 510k filing of SteriSet, including: 

• AMSCO Medallion Series 270oF deep and pulsing vac 

• AMSCO Eagle series 270oF prevac (pulsing) and express

• AMSCOMATIC Terminal 285 oF prevac (pulsing)

Details are reported in "Eagle SteriSet Technical Report: Design and Qualification" 

These tests demonstrated that SteriSet containers perform correct when sterilized with standard loads in a EN 285 resp. DIN resp. AMSCO steam sterilizer. However, hospitals are today in a situation, where more and more new instruments (new materials; holloware designs: example MIS instruments) are used: these produce a general compatibility problem, which can be expressed as follows:

• A container manufacturer (a manufacturer of any packaging material / system) cannot evaluate all possible load and cycle configurations which might ever be formed / combined out in the field.
  He can only validate his own packaging / container with standardized test loads / instruments against standardized - or well defined - sterilization cycles. 
  (Other packaging than containers, i.e. wrap or pouches, have the additional problem that you would need to define the WAY OF APPLICATION : single wrapped, double wrapped ? How to form / tape the pack?)
  
• A instrument manufacturer (specifically when we talk about ortho and neuro loaner instruments which come in nicely organized - but very compact and hard to re-process organizing sets) might argument that he cannot evaluate all possible PACKAGING and CYCLE configurations which might ever be formed / combined out in the field, but could only validate his INSTRUMENT SET inside a RECOMMENDED packaging in a standardized - or well defined - sterilization cycle.
  
• A sterilizer manufacturer cannot evaluate all possible packaging / load configurations which might ever be formed / combined out in the field, but can only validate his sterilizer / different cycles with standardized loads (metal; fabric) in standardized packaging materials.

How could any of the involved manufacturers - in view of a undefined potential of possible combinations in "real life" - ever claim that his product would have been validated, that it would so be safe to use in any combination in any hospital? 
Claiming a "validation" well knowing that at least one major parameter (i.e. the cycle) might be different in real application would be less than half of the truth, might even lead to a false sense of security in the hospitals!

This is the background for the requirement of on site validation of all possible configuration: where else than “on site” and how else than with the combination of packaging / load / cycle as used in daily application could you validate a process?  

European standard EN 554 gives here guidance on how to formally validate a steam sterilization cycle. 

Validation in that sense shall produce documented evidence, that the tested packaging/load/cycle configuration is capable to reproducably achieve sterile results.

Acc. EN554 that cannot be done by use of chemical or biological indicators, but needs sensitive recording of the temperatures inside a package during all stages of a cycle (thermocouples). 

Hospitals all over Europe are currently starting to validate their processes accordingly, but in most of the cases do not have the equipment neither the expertise to perform as required: consequently they use consultant companies or third party test labs for that purpose.

In case of SteriSet you would remove a handle on the short side (open the nuts inside – remove handle screws) and insert the thermocouples through that hole. After the validation you would re-assemble the handle.

PCDs (Process Challenging Devices

To ease the evaluation of “hollowware” (lumen devices) during steam sterilization there are currently ongoing standardization activities in Europe to develop “standardized hollowware test packs”: PCDs (Process Challenging Devices – described in EN 867-5 and the forthcoming international standard EN ISO 14937).

These would define “worst case” situations for steam penetration into lumens (like i.e. a Bowie&Dick test pack defines a worst case for air removal). PCDs shall be applied in every cycle / batch during routine operation: if at the end of the cycle the indicator (biological or chemical) which is contained in the PCD signals “sterile” there is a very high level of confidence that ALL PACKS which have been exposed in the same cycle are sterile.

Specifically in the absence of a thermometric validation the use of PCDs would drastically reduce risks caused by possibly insufficient steam penetration into lumens. PCDs are also recommendable for routine control of sterilization efficacy.