EP1935515A2

EP1935515A2 - A facility decontamination system

Info

Publication number: EP1935515A2
Application number: EP07150015A
Authority: EP
Inventors: Michael William Aitchison
Original assignee: Validated Hygiene Solutions Ltd
Current assignee: BIO DECONTAMINATION LIMITED
Priority date: 2006-12-13
Filing date: 2007-12-13
Publication date: 2008-06-25
Also published as: GB0624773D0; EP1935515A3

Abstract

A facility decontamination system has at least one nozzle (10) permanently sited within the facility (12), a liquid aerosol dispenser (14) located outside the facility and means (16) for coupling the external liquid aerosol dispenser (14) to the nozzle (10). The liquid aerosol dispenser means (14) has a reservoir containing a liquid decontaminant and propellant means (16) for expelling the liquid decontaminant from the reservoir means through the nozzle (10) into the facility (12). The decontaminant is preferably sprayed into the facility (12) as a dry fog and is subsequently evacuated.

Description

The present invention relates to systems for decontaminating sterile facilities such as clean rooms, sterile cabinets and ventilated cabinets for pharmaceuticals and biohazards. The present invention also relates to a method of decontaminating sterile facilities.
The risk of contamination in sterile facilities such as clean rooms, laboratories and the like is ever present and must be carefully guarded against. As stated in Endralex Vol. 4 Good Manufacturing Practice, Annex 1: "Manufacture of Sterile Medical Products", the transfer of materials into and out of the unit is one of the greatest potential sources of contamination. Materials which are commonly taken into and out of a sterile facility, and which represent a contamination risk, include raw materials, packaging, personnel and apparel, equipment, and cleaning and disinfectant materials. Research has shown that most of these are contaminated with bacteria and/or spores.
In order to prevent or at least minimise the risk of contamination a number of procedures are recommended. These include disinfecting all materials before taking them into the facility, requiring personnel entering/leaving/accessing the facility to wear appropriate apparel, minimising the amount of paper used within the facility, ensuring that disinfectants are sterile, and staff training. However, it is still necessary from time to time to clean and sterilise the facility. This entails cleaning operatives washing the facility with cloths, mops and buckets of chemical to clean down all the inside surfaces of the facility. Next a mobile sterilisation unit is positioned in the facility. The mobile sterilisation unit sprays a dry fog of hydrogen peroxide into the facility which disperses over all of the inside surfaces to disinfect and sterilise these. Once the dry fog cycle is completed the mobile sterilisation unit is removed from the facility. The sterilisation process is validated using biological indicators (Geobacillus stearothermophilus). Cultures of these are placed in the facility and exposed to the disinfection, after which they are cultured in a suitable media and under appropriate recovery conditions as specified by the manufacturer. If no growth occurs, the disinfection process is deemed to have worked.
It will be appreciated that the conventional method of cleaning and sterilising a facility requires both cleaning operatives and their equipment to enter and leave the facility on a number of occasions. Each time this takes place there is a risk of contamination, from both the operatives and from the equipment they use. Furthermore, the conventional mobile sterilisation unit employed to spray hydrogen peroxide into the facility requires a pressurised air supply. This too can represent a potential source of contamination.
It is an object of the present invention to provide a facility decontamination system which substantially avoids the need for personnel and equipment to enter a facility to carry out cleaning and sterilising procedures.
It is yet another object of the present invention to provide a method of cleaning and sterilising facilities.
According to a first aspect of the present invention, there is provided a facility decontamination system comprising at least one nozzle permanently sited within the facility, a liquid aerosol dispenser located outside the facility and means for coupling the external liquid aerosol dispenser to the said at least one nozzle, the liquid aerosol dispenser means comprising reservoir means containing a liquid decontaminant and propellant means for expelling the liquid decontaminant from the reservoir means through the said at least one nozzle into the facility.
In one embodiment, the liquid aerosol dispenser means is adapted to dispense a plurality of different decontaminant liquids, sequentially, through the at least one nozzle into the facility.
The reservoir means may comprise a single container and may be adapted to receive, sequentially, a plurality of different decontaminants.
Alternatively, the plurality of decontaminant liquids may be held in separate containers and the system may further comprise valve means for connecting propellant means sequentially to the plurality of decontaminant liquids.
Preferably, the system comprises means for operating the propellant means for a predetermined period after the reservoir means has been emptied of decontaminant liquid, in order to clear the container, the coupling means and the said at least one nozzle of the decontaminant liquid.
The liquid may comprise a detergent, for example an enzyme-based detergent.
The decontaminant liquid may comprise a disinfectant, such as hydrogen peroxide and/or peracetic acid.
The decontaminant liquid may also comprise a substance to neutralise the disinfectant.
Preferably, the system also comprises means for evacuating the decontaminant vapour from the facility.
The means for evacuating the decontaminant vapour from the facility may comprise an air management system.
Alternatively, or in addition, the system may further comprise filter or trap means through which the decontaminant vapour is discharged. The filter or trap means may comprise a substance which reacts with the decontaminant vapour. Preferably, a valve means is located between the facility and the filter or trap means.
Preferably, the system further comprises control means for selectively controlling the supply of decontaminant liquid to the said at least one nozzle and for controlling the propellant means.
Preferably, the said at least one nozzle produces a dry fog within the facility.
The present invention also includes a sterile facility comprises a facility decontamination system in accordance with the present invention.
In accordance with a second aspect of the present invention, there is provided a method of decontaminating a sterile facility, comprising:

spraying a decontaminant into the facility as a dry fog; and
evacuating the decontaminant vapour from the facility.

In one embodiment, a plurality of decontaminants are dispensed, sequentially, through the said at least one nozzle into the facility.
The decontaminant liquid may comprise a detergent, for example an enzyme-based detergent.
The decontaminant liquid may comprise a disinfectant, for example hydrogen peroxide and/or peracetic acid.
The decontaminant liquid may also comprise a substance to neutralise the disinfectant.
Preferably, the decontaminant vapour is evacuated from the facility via an air management system.
Alternatively, or in addition, the decontaminant vapour may be discharged through a filter or trap means. The filter or trap means may comprise a substance which reacts with the decontaminant vapour.
An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawing which shows a schematic view of a facility decontamination system in accordance with the present invention.
Referring to the drawing there is shown a facility decontamination system in accordance with the present invention. The system comprises one or more nozzles 10 which are permanently sited within a clean room 12. The nozzle or nozzles 10 is/are are so positioned within the clean room as to ensure that material sprayed therefrom reaches the entire volume of the clean room and all or substantially all of the internal surfaces of the clean room.
Each of the nozzles 1 is coupled to a liquid aerosol dispenser 14 via a valve 16, the dispenser comprising reservoir means (not shown) for containing liquid decontaminants such as liquid detergent and liquid disinfectant and a neutraliser for liquid disinfectant. The liquid aerosol dispenser 14 also comprises propellant means 16 in the form of an air compressor or compressed gas cylinders or the like for dispelling liquid from the reservoir means through the or each of the nozzles 10 into the clean room. The supply of compressed gas to the liquid aerosol dispenser is controlled by a valve 18. The compressed gas is also supplied directly to the nozzle or nozzles 10 through a separate supply line 20 via a further regulating valve 22, in order to produce a dry fog of the liquid decontaminant, as will be explained.
The reservoir means may comprise a single container which can be filled with decontaminant liquid and is discharged into the clean room until the container is emptied. If more than one decontaminant liquid is to be used, each one may in turn be loaded into the reservoir means and discharged. Alternatively, the reservoir means may comprise two or more such containers and the propellant means is switched between them.
The nozzles 10 function in the usual way, expelling liquid from the container 3 under pressure from the propellant means through a nozzle outlet to form a fine mist or aerosol inside the clean room.
Once a container of decontaminant liquid has been emptied of liquid the propellant means 16 is operated for a further predetermined period to clear the lines coupling the aerosol dispenser 14 to the nozzle or nozzles 10 (and to clear the nozzle or nozzles themselves) and prevent contamination if a further liquid is introduced.
The system further comprises control means 24, illustrated schematically, for controlling and regulating operation of the liquid aerosol dispenser 14, the propellant means 16 and the valves 16, 18, 22. The control means 24, which may conveniently be a programmed microprocessor, controls the operation of the liquid aerosol dispenser 14 to selectively supply liquid decontaminant material and air or gas to the nozzle or nozzles 10 as will be described hereinafter.
The facility decontamination system may be operated to discharge one, or more than one, decontaminant liquid into the clean room 10.
For example, a decontamination cycle may comprise:

discharging of only a detergent (such as an enzyme-based detergent e. g. a mixture of water, coconut oil, amphoteric surfactant, trisodium gluconate, sodium chloride, sodium hydroxide and citrus dulcis); or
discharging a disinfectant liquid (e.g. hydrogen peroxide solution or a mixture of hydrogen peroxide and peracetic acid).

Alternatively, more than one decontaminant liquid may be used, sequentially. For example, the cycle may comprise, sequentially:

The sequential discharge of a detergent and then the discharge of a disinfectant; or
the sequential discharge of a detergent, a disinfectant and a neutralising agent for the disinfectant; or
the sequential discharge of a disinfectant agent and a neutralising agent.

However, whenever a liquid decontaminant is discharged into the room, it is discharged as a non-wetting mist or dry fog. For the purposes of explanation, the droplets or liquid in a dry fog are very small, typically 10 microns or less in diameter, and tend to bounce off surfaces. Droplets of liquid larger than this tend to burst on contact with a surface and wet the surface.
As mentioned previously, after the or each liquid is discharged into the clean room, the propellant means 16 is operated for a further predetermined period to clear the lines coupling the aerosol dispenser to the nozzles and to clear the nozzle itself, and to prevent contamination if a further liquid is to be discharged.
The dry fog of liquid contaminant is allowed to remain in the clean room for a length of time sufficient for it to carry out its purpose, for example, cleaning the surfaces of the room if a detergent is used carrying out effective sterilisation of the interior surfaces of the clean room if a disinfectant is used and neutralising the disinfectant if a neutralising agent is used.
As indicated schematically in the drawings, for a clean room having a conventional air management system 26, the air management system (under the control of the control means 24) is operated after the or each dry mist or fog has been allowed to remain in the clean room for the require period of time. Alternatively, or in addition, the dry mist or fog may be evacuated through a filter or trap means 28 connected to an external fan 30 under the control of the control means 24. A valve 32 is interposed between the clean room and the filter means, and is also under the control of the control means 24.
The filter means may comprise an adsorbent material such as activated charcoal to absorb the vapour being evacuated, or may comprise a substance which reacts with the vapour being evacuated. For example, if a hydrogen peroxide fog is being evacuated, the filter or trap means may comprise a solution of potassium permanganate which reacts with the hydrogen peroxide and neutralises it. If a filter 28 is provided, then it may not be necessary to discharge a neutralising substance into the clean room to neutralise the disinfectant vapour. Effectively, the neutralisation takes place upon evacuation of the disinfectant vapour, which can considerably reduce the length of time of the decontamination cycle.
To complete the cleaning process chemical residue tests can be carried out to confirm that levels are below the levels recommended by the Health and Safety Executive.
The facility decontamination system of the present invention is less expensive than conventional mobile systems. Once the nozzles have been installed in a clean room the only major on-going cost lies in the cleaning chemicals. The liquid aerosol dispenser which is coupled to the nozzles can be employed with a number of clean rooms being connected up whenever a clean room requires to be cleaned and disconnected afterwards.
The exposure of staff to cleaning chemicals is much reduced in that the only time they come into contact with these is when filling the liquid aerosol dispenser.
The invention is not restricted to the details of foregoing embodiment. For example, although the embodiment has been described with reference to a clean room, the invention is equally applicable to other sterile facilities such as sterile cabinets, ventilated cabinets and the like.
In addition, if an external filter or trap means 28 is used, then it would be possible to dispense within the external fan and to evacuate the vapour through the filter or trap means 28 by increasing the internal pressure within the clean room or other facility.
Moreover, although the embodiment as described is operated by the control means, it would be possible to dispense with the control means and operate the various components of the system manually, if desired.

Claims

A facility decontamination system comprising at least one nozzle permanently sited within the facility, a liquid aerosol dispenser located outside the facility and means for coupling the external liquid aerosol dispenser to the said at least one nozzle, the liquid aerosol dispenser means comprising reservoir means containing a liquid decontaminant and propellant means for expelling the liquid decontaminant from the reservoir means through the said at least one nozzle into the facility.
A facility decontamination system as claimed in claim 1, wherein the liquid aerosol dispenser means is adapted to dispense a plurality of different decontaminant liquids, sequentially, through the at least one nozzle into the facility.
A facility decontamination system as claimed in claim 2, wherein the reservoir means comprises a single container and is adapted to receive, sequentially, a plurality of different decontaminants.
A facility decontamination system as claimed in claim 2, wherein the plurality of decontaminant liquids are held in separate containers and wherein the system further comprises valve means for connecting the propellant means sequentially to the plurality of decontaminant liquids.
A facility decontamination system as claimed in any of the preceding claims, comprising means for operating the propellant means for a predetermined period after the reservoir has been emptied of decontaminant liquid, in order to clear the container, the coupling means and the said at least one nozzle of the decontaminant liquid.
A facility decontamination system as claimed in any of the preceding claims, wherein the decontaminant liquid comprises a detergent.
A facility decontamination system as claimed in claim 6, wherein the detergent is an enzyme-based detergent.
A facility decontamination system as claimed in any of the preceding claims, wherein the decontaminant liquid comprises a disinfectant.
A facility decontamination system as claimed in claim 8, wherein the disinfectant comprises hydrogen peroxide.
A facility decontamination system as claimed in claim 8 or claim 9, wherein the disinfectant comprises peracetic acid.
A facility decontamination system as claimed in any of claims 8 to 11, wherein the decontaminant liquid comprises a substance to neutralise the disinfectant.
A facility decontamination system as claimed in any of the preceding claims, comprising means for evacuating the decontaminant vapour from the facility.
A facility decontamination system as claimed in claim 12, wherein the means for evacuating the decontaminant vapour from the facility comprises an air management system.
A facility decontamination system as claimed in claim 12 or claim 13, further comprising filter or trap means through which the decontaminant vapour is discharged.
A facility decontamination system as claimed in claim 14, wherein the filter or trap means comprises a substance which reacts with the decontaminant vapour.
A facility decontamination system as claimed in claim 14 or claim 15, further comprising valve means between the facility and the filter or trap means.
A facility decontamination system as claimed in any of the preceding claims, further comprising control means for selectively controlling the supply of decontaminant liquid to the said at least one nozzle and for controlling the propellant means.
A facility decontamination system as claimed in any of the preceding claims, wherein the said at least one nozzle produces a dry fog within the facility.
A facility decontamination system substantially as herein described, with reference to, and as illustrated in, the accompanying drawing.
A sterile facility comprising a facility decontamination system as claimed in any of the preceding claims.
A method of decontaminating a sterile facility, comprising:
spraying a decontaminant into the facility as a dry fog; and

evacuating the decontaminant vapour from the facility.
A method as claimed in claim 21, comprising dispensing a plurality of different decontaminants, sequentially, through the said at least one nozzle into the facility.
A method as claimed in claim 21 or claim 22, wherein the decontaminant liquid comprises a detergent.
A method as claimed in claim 23, wherein the detergent is an enzyme-based detergent.
A method as claimed in any of the preceding claims, wherein the decontaminant liquid comprises a disinfectant.
A method as claimed in claim 25, wherein the disinfectant comprises hydrogen peroxide.
A method as claimed in claim 25 or claim 26, wherein the disinfectant comprises peracetic acid.
A method as claimed in any of claims 25 to 27, wherein the decontaminant comprises a substance to neutralise the disinfectant.
A method as claimed in any of the preceding claims, comprising evacuating the decontaminant vapour from the facility via an air management system.
A method as claimed in any of claims 21 to 29, comprising discharging the decontaminant vapour through a filter or trap means.
A method as claimed in claim 30, wherein the filter or trap means comprises a substance which reacts with the decontaminant vapour.
A method of decontaminating a sterile facility substantially as herein described with reference to, and as illustrated in, the accompanying drawings.