Six commercially available Class 6 chemical Indicators tested against their stated values.

J.P.C.M van Doornmalen, R.J. Hermsen and K. Kopinga
Central Service 6/2012


Current reference devices for hollow instrument loads as defined in standards are not a valid steam penetration test.

Essen, S., Tessarolo, F., Hermsen, R., & Van Doornmalen, J. (2012).

Central Service , 4, 256-260.


A comparison of four commercially available electronic steam penetration tests according to ISO 11140 part 4

Benoit, F., Merger, D., Hermsen, R., & Van Doornmalen, J. (2011).Central Service , 3.