What is the difference between disinfection and sterilization?
Disinfection destroys all the micro-organisms present in a given environment apart from spores: an object that has been disinfected properly may still transmit a pathogenic micro-organism. Sterilization, on the other hand, is the complete elimination of all micro-organisms including spores.

What are the main features of steam sterilization?
Heat is the best and most used sterilization agent and pressurized, saturated water vapour is the most efficient method of heat transmission. That is why steam sterilization reduces the time and the temperature needed for the treatment: at 134 °C an exposure of only 4 minutes is sufficient, at 121 °C a time of 15 minutes is enough. In addition, steam sterilization creates no toxic or dangerous residues on objects and does not damage instruments (provided that they can withstand the temperatures reached).

What is EN 13060?
This is the applicable European standard, relating to small steam sterilizers. Cominox® has since 1996 been an active member of the WG5 work-group of the European Committee for Standardization's TC 102 technical commission, working on the drafting of EN 13060.

What is a Type-B autoclave?
EN 13060 distinguishes between three types of cycle:
B cycle for sterilizing all objects (solid instruments, porous objects and A and B hollow objects, both packaged and un-packaged);
N cycle for sterilizing only un-packaged solid instruments;
S cycle for sterilizing un-packaged solid instruments plus one other of the types indicated for cycle B (to be specified by the maker).
Type B autoclaves are autoclaves that can carry out cycle B and thus can sterilize any kind of object.

What is the sterilization temperature band?
EN 13060 lays down that during sterilization the following nine temperatures - eight measured at different points within the load and the unoccupied space remaining in the chamber and the last a reading taken on the saturation vapour curve according to the pressure measured in the chamber - must be above the sterilization temperature, but not by more than 4 °C (e.g. for a cycle at 134 °C the readings must be between 134 and 138 °C, the sterilization range). In addition, there must not be more than a 2°C difference between any one reading and another at any given time. This guarantees that the conditions necessary for sterilization are kept constant and uniform throughout the period of exposure and, by means of a comparison of temperature to pressure on the saturation vapour curve, that the air has been properly removed prior to sterilization.

What are the pre-vacuum phase and any vacuum pulse phase for?
These are necessary for the removal of air from the autoclave chamber, given that at any given pressure and temperature the density of air is around 1.5 times that of steam, such that any air present during sterilization settles in the lower part of the chamber and creates so-called "air pockets", where the temperature is not controlled and this is potentially deleterious as far as sterilization quality is concerned.

Why is drying important?
With packaged objects drying is vital to guarantee the sterility of the instruments contained in packages while in storage: the packages must be dry when removed from the autoclave at the end of the cycle, otherwise they might immediately become contaminated again.
What is the Bowie & Dick Test for?
Its purpose is to check the degree of steam penetration in the case of porous objects (e.g. gauze or fabric) and the efficiency of the air removal system. The test kit normally consists of treating a package containing a chemical process indicator according to a special sterilization cycle at 134°C for 3.5 minutes. The test is positive if the chemical indicator changes colour in line with the information given by the producer of the test kit.

What is the Vacuum or Air Leakage Test for?
This is used to test the efficacy of the air removal system and that the hydraulic system is perfectly air-tight. The test is defined according to EN 13060, which lays down that there must be a cycle that carries out this test automatically on all autoclaves that have a vacuum phase for removing air. For this test at least the vacuum phase is carried out as in the highest performing cycle offered by the machine, then the chamber is kept in isolation for a certain length of time and the increase in pressure due to any re-entry of air is checked to make sure it is lower than a pre-defined value.

What is the Helix Test for?
Its purpose is to check the degree of steam penetration in the case of hollow objects and the efficacy of the air removal system. The test uses a Teflon tube open at one end only (length 1.5 m, internal diameter 2 mm), ending with a Teflon capsule, containing a chemical process indicator. EN 13060 requires for purposes of approval the employment of this apparatus to test cycles for sterilizing hollow load A (for example B cycles). The test is positive if the chemical indicator changes colour in line with the information given by the producer.
The thermometer test described in the answer to F.A.Q. What is the sterilization temperature band? is not required for hollow load A, in that it is not possible to make a precise measurement of the temperature reached at the back of the cavity of the apparatus described above.

Must a printer be used?
EN 13060 requires the presence of a process evaluation system and/or recorder. The latter can be analogue or digital and must produce a record (in the form of a chart on an electronic or paper support) in which temperature and pressure are sampled by means of sensors that are independent of those of the sterilizer at least every 2.5 seconds. Usually the printers that form part of the small sterilizers do not meet these requirements and are therefore not obligatory. Nevertheless, a printer is useful for collecting and filing information regarding the cycle and the objects sterilized and for identifying causes of anomalies.

What is a process evaluation system for?
EN 13060 requires the presence of a process evaluation system and/or recorder. The former must automatically monitor the factors essential to ensuring sterilization and must indicate to the operator if the cycle is acceptable or not. In particular, a process evaluation system should answer the same questions as those a well-trained operator would pose when examining the record of the cycle to say whether it has been completed correctly or not:
· Was the pressure in the pre-vacuum phase and the succeeding vacuum pulses low enough?
· Was the time taken to reach it within the allowed limits?
· Was the pressure at the steam peaks high enough?
· Was the time taken to reach it within the allowed limits?
· Was the pressure during sterilization within the allowed limits?
· Was the time taken to reach it within the allowed limits?
· Was the temperature during sterilization within the allowed limits?
· Did the sterilization last long enough?
· Was the pressure in the drying phase low enough?
· Did the drying last long enough?
In a word, he has to be able to identify specific anomalies relating to the process or the autoclave.

What is the difference between type A and type B hollow loads?
According to the definition in EN 13060 type A hollow objects are instruments with an open cavity on only one side where the ratio of length to diameter of the cavity is greater than or equal to 1 and less than or equal to 750 (1 = L/D = 750) and where the length of the cavity is not greater than 1500 mm (L = 1500 mm); or, alternatively, instruments with an open cavity on both sides where the ratio of length to diameter of the cavity is greater than or equal to 2 and less than or equal to 1500 (2 = L/D = 1500) and where the length of the cavity is not greater than 3000 mm (L = 3000 mm). Type B hollow objects, on the other hand, are instruments with an open cavity on only one side where the ratio of length to diameter of the cavity is greater than or equal to 1 and less than or equal to 5 (1 = L/D = 5) and where the diameter of the cavity is greater or equal to 5 mm (D = 5 mm); or, alternatively, instruments with an open cavity on both sides where the ratio of length to diameter of the cavity is greater than or equal to 2 and less than or equal to 10 (2 = L/D = 10) and where the diameter of the cavity is greater or equal to 5 mm (D = 5 mm).
The Cavity diameter (D) / Length (L) chart below shows the areas relating to type A (in blue) and type B (in orange) hollow bodies with an open cavity on only one side (for those with an open cavity on both sides, for any given cavity diameter, double the length to obtain the equivalent diagram). The space above these areas relates to those bodies where the ratio of length to diameter of the cavity is too big for them to be sterilized even with B cycles; the space below relates to bodies that are not hollow but solid.