GB2491974A

GB2491974A - A building module for a modular forensic laboratory.

Info

Publication number: GB2491974A
Application number: GB1210579.7A
Authority: GB
Inventors: Robert Lee
Original assignee: MARSHALL SPECIALIST VEHICLES Ltd
Current assignee: MARSHALL SPECIALIST VEHICLES Ltd
Priority date: 2011-06-15
Filing date: 2012-06-14
Publication date: 2012-12-19
Anticipated expiration: 2032-06-14
Also published as: GB2491974B; GB201110098D0; GB201210579D0

Abstract

The module comprises a shelter having external dimensions of a conventional ISO shipping container and being adapted to contain air at a pressure in excess of the external ambient atmospheric pressure, creating a positive pressure or over pressure environment. The module also comprises an air flow control system comprising: i) An air intake 14 ii) At least one fan to draw air into the module iii) At least one HEPA filter 26 iv) A diffuser v) A sensor to measure the absolute or relative air pressure within the module vi) A feedback control mechanism to adjust the flow of air based on the output from the sensor (v) so as to maintain a desired air pressure within the module. The feedback control means may adjust the speed of the fans (ii) or there may be a booster fan 22 to affect an air flow rate. Also included is a item communication device portal with two openings but allows only one to open at a time between rooms of varying pressure.

Description

Title: Modular Shelter System

Field of the Invention

The present invention relates to a modular shelter system, to a module for use therein, and to a method of assemblying a modular shelter system.

Background of the Invention

It is known to provide deployable shelters having the external dimensions of standard ISO containers, which facilitates transport of the shelter by ship, transport aircraft and io by road. Such shelters may be used as command, communications and control centres or as medical facilities (see e.g. GB 2472794, GB 2472888).

There are some specialised uses for deployable shelters, such as use as a forensic laboratory, for which uses the presently-available shelters are not specifically is designed and they are not therefore compatible with such uses.

For example, in a laboratory in which molecular biological amplification reactions are being performed, such as the polymerase chain reaction (PCR), it is extremely important to prevent the entrance of contaminating nucleic acid, otherwise the contaminant may also be subject to amplification, and thus possibly swamp the actual sample or at least lead to confusing and unreliable results. Other amplification reactions may also be similarly affected (e.g. ligase chain reaction or LCR, and NASBA). The present invention seeks, in preferred embodiments, to provide a deployable modular shelter system which is adapted and configured for use as a forensic laboratory, and which is much more suitable for such use than existing deployable shelters.

Summary of the Invention

In a first aspect the invention provides a modular system comprising a plurality of deployable shelters which combine to form a multi-roomed facility; each module being provided with an individual air flow control means; and wherein the air in at least one of the rooms of the facility is, in use, maintained at a pressure in excess of ambient atmospheric pressure.

Advantageously, each of a plurality of rooms in the facility are, in use, maintained at a pressure in excess of ambient atmosphere pressure. The plurality of rooms may be in a single module or may be in two or more modules. Accordingly, in a preferred embodiment the facility will comprise at least two modules, each module having at least one room which, in use, has an air pressure maintained in excess of ambient air pressure. Conveniently, substantially the entire working space within one or more modules will, in use, contain air maintained at a pressure in excess of ambient atmospheric pressure.

For present purposes, the term "air" encompasses not only air but also breathable gas mixtures which are capable of maintaining human life. Examples of such breathable gas mixtures include air supplemented with oxygen, or nitrogen supplemented with oxygen etc. In a second aspect, the invention provides a module for use in the system of the first aspect, the module comprising a shelter having extemal dimensions substantially corresponding to those of a conventional ISO container, the module being adapted and configured, in use, to contain air at a pressure in excess of external ambient pressure, the module further comprising air flow control means including (i) an air intake; (ii) one or more fans to draw air into the interior of the module; (iii) at least one HEPA filter to filter the air; (iv) a diffuser to deliver a diffuse flow of air to the interior of the module; (v) at least one sensor to measure the absolute or relative air pressure within the module; and (vi) feedback control means to increase or decrease the flow of air into the module based on the output from the sensor (v) so as to maintain a desired absolute or relative air pressure within the module.

Conveniently, the feedback control means (vi) acts by increasing or decreasing the speed of the fan or fans (ii) to vary the flow of air into the module. Typically the fan speed may be adjusted by varying the amount of electrical power supplied to the fan(s) (e.g. by varying the voltage). The fan or fans (ii) may be known as "fresh air intake fans".

The sensor (v) can measure the pressure at any desirable location within the module.

If the entire module is not to be maintained, in use, at a pressure in excess of ambient atmospheric pressure, then clearly it is desirable to locate the sensor within that part of the module which is to be pressurised.

In a preferred embodiment an air circulation fan (vii) is also provided in the module.

This fan will generally have a higher capacity than the one or more fresh air intake fans (ii), and accordingly fan (vii) may be termed a "booster" fan. The function of the booster fan is to force a desired volume of air per unit time through the module. To help accomplish this, it is preferred that the module comprises at least one further sensor (viii), which sensor measures the flow rate of air through the module (typically is in the air flow control means thereof), which flow rate may be measured or monitored in absolute terms or in relative terms, as desired. Preferably the flow rate is measured or monitored in absolute terms.

Conveniently the module will comprise a further feedback control means (ix) to vary the rate of flow through the module based on the output from the at least one flow rate sensor (viii), so as to maintain a desired rate of flow of air through the module.

Desirably the feedback control means (ix) will operate by varying the speed of the booster fan (vii), typically by varying the amount of electrical power supplied to the booster fan (e.g. by varying the voltage).

Preferably the module is asymmetrically divided by an internal partition into a main working space and a smaller space. In a preferred embodiment, the main working space is equipped as a laboratory (e.g. a laboratory to handle and process biological samples) and the smaller space is a gowning area, in which workers may don clean (preferably sterile) lab coats, hats, overshoes etc. before entering the laboratory space.

In particular, the laboratory may be equipped to perform a nucleic acid amplification reaction, such as PCR, and/or a DNA analysis technique such as DNA sequencing, restriction fragment length polymorphism (RFLP) analysis, or genetic fingerprinting and the like. Amplification reactions in particular are vulnerable to contaminants since, if non-sample derived DNA contaminates the sample, the contaminating DNA may be amplified which may swamp the actual sample DNA, or at least cause the generation of ambiguous and/or misleading results in subsequent analyses.

The partition will conveniently comprise a doored aperture, to allow persons to move between the laboratory and the gowning space. The aperture may conveniently be surrounded by sealing means, such as an elastomeric polymer (e.g. a silicone rubber), to form a substantially air-tight seal between the laboratory and the gowning space io when the door is closed.

As mentioned above, the module is adapted and configured to contain air at a pressure in excess of ambient pressure and, when the modular system is assembled, the air in some rooms will desirably be at a higher pressure than the air in neighbouring rooms.

is Such pressure differences may exist between modules, and/or within a single module (e.g. between a laboratory and a gowning space). The pressure in excess of ambient, or in excess of neighbouring rooms, should be high enough to be effective in reducing the ingress of contaminants.

However, the pressure differential cannot be too great, otherwise considerable effort is required to open and close doors between neighbouring rooms, or between the facility and the external environment. Accordingly a balance must be struck, and careful control of the air-flow within the facility is required to maintain the desired absolute pressures and pressure differentials.

As a general rule, a "pressure cascade" may preferably exist in the facility, in which the highest pressure is maintained e.g. in a laboratory in which a sample amplification (e.g. PCR) step is performed, with other rooms held at an intermediate pressure (e.g. an adjacent gowning area) and still other rooms held at a lower pressure, whilst still above external ambient pressure (e.g. an entrance room or vestibule into which people pass upon first entering the facility from the external environment). Typical pressures might be 140-180 Pa in excess of ambient for the highest pressure areas, 120-150 Pa in excess of ambient for intermediate pressure areas, and 70-120 in excess of ambient for lowest pressure areas.

Typically, there is a trend of increasing pressure as one progresses from the outermost room towards the highest pressure area in the facility. Conveniently there is at least one transition across a pressure differential, more preferably at least two transitions, and most preferably three or more transitions, each transition being from a room or zone with a relatively low pressure to a room or zone with a relatively high pressure, such that the ingress of airborne contaminants across the transition is rendered less io likely than if the pressure differential did not exist.

As each module in the system desirably has its own air intake and air flow control system, it is relatively simple to assemble the modules to form the system of the first aspect. In addition, a greater degree of control is attainable over the air pressure in is each module than if a single air flow control system was provided to operate throughout the facility, and this facilitates the maintenance of the multiple pressure differentials preferably formed with the facility.

The air flow control system delivers sufficient fresh air to create comfortable working conditions within each module. Current guidelines suggest a minimum flow of 8 litres per second per person and, depending on the number of people working in the module, the air flow control system will generally be designed and adapted to provide an air flow through the module of about 100 m3/hour.

Typically air drawn into a module is passed through the HEPA filter and then supplied, via ducting, to the diffuser, or "sock", which delivers a diffuse flow of air into the working space inside the volume. The diffuser preferably comprises a synthetic fabric with a permeability sufficient to bleed a desired volume of air into the module. To this end the diffuser preferably has a relatively large surface area (e.g. about 1.0-2.5m2 more especially about 1.5 to 2.2m2).

The module of the second aspect of the invention will comprise at least one sensor to monitor the absolute or relative air pressure within the module. More preferably, a plurality of sensors are provided, such that the absolute or relative air pressure at two or more different locations within the module can be measured. In order to measure the air pressure within the module relative to the external ambient air pressure, it will be convenient to have a sensor which is exposed to the external environment. The applicant has found that this can best be accomplished by providing a chimney, conduit or other fluid-communicating bore -which rises above the exterior of the module. By way of explanation, air flow nearer to the ground can be very turbulent, so the determined atmospheric pressure can fluctuate rapidly e.g. with gusts of wind, making accurate measurements difficult.

In contrast, at a height of 3 metres or so above the ground, the flow of air is much less turbulent and approximates to laminar flow conditions. The air pressure at that height is therefore far less prone to rapid fluctuation, and allows for easier measurement. It is preferred therefore that the module of the invention is provided with a chimney, is conduit or the like which extends above the roof of the shelter. This can be made collapsible, to facilitate transport of the shelter, or can be made readily releasable, such that the chimney can be removed for transit and attached or raised when the module is in situ.

With use, the one or more filters in the module may tend to become partially blocked e.g. with dust, sand, pollen grains, micro-organisms, etc. This increases the resistance of the filter to air flow, which can be detected e.g. by measuring the air pressure differential across the filter. Accordingly it is preferred to have at least one sensor or meter associated with at least one filter, (preferably each filter), such that the behaviour of the filter can be checked intermittently or continuously monitored. If a characteristic, such as the air flow or air pressure differential across the filter, falls outside a pre-determined acceptable range, an audible and/or visual alarm may be triggered, indicating that the filter needs to be cleaned and/or replaced.

Preferably the module comprises a control box, which may typically comprise a microprocessor or the like, which monitors the signals from the various sensors or meters provided in the module, and determines what adjustments, if any, need to be made to the components of the air flow control system e.g. opening or closing one or more valves, or vents, adjusting fan speed etc. This forms part of the feedback control means (vi), and optional feedback control means (ix).

In one embodiment, it is desirable to provide a communication means between two adjacent rooms of the facility, to allow the physical transfer of samples, but which communication means is too small to allow people to move between the rooms. The communication means should ideally have dimensions which are as small as are compatible with the convenient transfer of samples between the rooms, so as to minimise the chance of the ingress of contaminants. The communication means io should preferably be sealable, such that when a sample is not actually being transferred, a substantially air-tight seal exists across the communication means.

The communication means may be between one room and another room in the same module or, more preferably, the communication means may be provided between two is different modules. The communication means may, for example, be provided between a module in which a nucleic acid amplification reaction is performed and a module in which a downstream processing or analysis step is performed on the amplified sample (e.g. a "Post-PCR" module). Altematively, or additionally, a communication means may be provided between a module in which a nucleic acid amplification reaction is performed and a module in which an upstream processing step is performed (e.g. an "admin" module).

The communication means conveniently takes the form of a substantially air-tight tunnel, pipe, conduit, channel or the like, between the two communicating rooms or modules. Each end of the communication means typically comprises an openable hatch or cover, to allow one or more samples to be delivered into, or recovered from, the communication means. The hatch or cover may comprise a transparent material, such as glass or perspex, to allow samples inside the communication means to be seen when the hatch or cover is closed. In order to reduce the likelihood of the transfer of airborne contaminants, the communication means will desirably be provided with a simple physical and/or electrical interlock mechanism, to prevent the hatch or cover at each end of the communication means being open simultaneously -thus, when the hatch or cover at one end is open, the hatch or cover at the other end must be closed.

n a preferred embodiment, each module may also provided with its own, independent, temperature regulation system. Conveniently the temperature regulation system comprises an air conditioning unit. lEn one embodiment, air is withdrawn from the interior of the module and passes through a heat exchanger of an air conditioning unit. Typically, the air so cooled is then mixed with fresh, incoming air before recirculation into the interior of the module.

In a third aspect, the invention provides a method of making a multi-roomed facility io from a plurality of deployable modular shelters, the method comprising the steps of: (a) deploying a plurality of modules in accordance with the second aspect of the invention; and (b) forming a substantially air-tight access-way for personnel between at least two of the plurality of modules.

The facility will preferably comprise a plurality of pressure gauges and/or air flow gauges which are centrally located in a single module (e.g. an "admin" module) and which allow centralised inspection at one location of the pressure and/or air flow rates at different, remote, locations within the facility. To allow for this, it is necessary for the centralised gauges to be fluidically connected to the remotely monitored locations, and such connections should be made as an optional step in the assembling and deployment of the facility. To facilitate this, one or more of the modules will be conveniently provided with push-fit or snap-fit, and quick release, air pressure tube couplings (e.g. Camozzi fittings) which are commercially available. The couplings may be colour-coded, or be formed with some other visual indicator, to ensure appropriate connections are made when the facility is assembled.

On commissioning the deployed system, it is preferred to pressurise that part of the facility which has the highest air pressure, before pressurising the rest of the facility.

Generally, the order of pressurisation should follow from highest desired pressure down to lowest desired pressure. This reduces the risk of the ingress of contaminants.

Other aspects of deployment of the system will be known to those skilled in the art from conventional deployable shelter systems. These include, for example, levelling means, such as height-adjustable struts or other supports, to ensure that the floor of the shelter is substantially horizontal, and that preferably the floors of adjacent shelters are at substantially the same height. (e.g. preferably within 20 mm, more preferably within 10 mm, and most preferably within 5 mm).

In addition, one or more exterior surfaces of the shelters or modules are desirably formed with registration marks to facilitate positioning and adjustment of the shelters.

For the avoidance of doubt, it is hereby expressly stated that features of the invention described herein as "preferred", "advantageous", "desirable", "convenient" or the like may be used in the invention in isolation, or in any combination with one or more other such features so described, unless the context dictates otherwise. Similarly, is features described as "preferred", etc., as stated above, in relation to one aspect of the invention will generally be understood to relate also to the other aspects of the invention, inutatis inutandis, unless the context dictates otherwise.

The invention will now be further described by way of illustrative embodiment and with reference to the accompanying drawings, in which: Figure 1 is a sectional view, seen from above, of a multi-roomed facility in accordance with the first aspect of the invention, comprising three modules in accordance with the second aspect of the invention; Figure 2 is a schematic representation of the embodiment of the invention shown in Figure 1, and indicates the relative pressures and pressure differentials designed to be maintained in the facility when operational; Figure 3 is a schematic plan view illustrating the air flow control system components, and the general direction of air flow within the system, in a single module in accordance with the invention; and Figure 4 is a schematic representation of a central pressure monitoring control for the embodiment of the facility shown in Figures 1 and 2.

Detailed Description of an embodiment

One embodiment of a modular system in accordance with the invention is illustrated schematically in Figure 1. The system, denoted generally by reference numeral 2, comprises three deployable shehers or modules 4, which combine to form a muhi-roomed forensic laboratory, intended, in this instance, to perform PCR amplification of nucleic acid samples and then to analyse the amplified samples e.g. by genetic fingeiprinting. Each module 4 is in accordance with the second aspect of the invention.

The samples are received first in module 4a, an "Admin" unit, and then passed to module 4b ("Pre-PCR"), in which the amplification step takes place. The amplified is samples then pass to module 4c ("Post-PCR") for downstream processing, such as genetic fingerprinting.

Each module or sheher 4 has metal walls (e.g. steel) and is substantially similar, having external dimensions substantially corresponding to a standard ISO container, so that the individual modules are readily transportable using conventional transport methods and equipment.

Each module 4 comprises a laboratory space 6 and a smaller vestibule or gowning area 8. Each module is also provided with its own air flow control system and its own air conditioning unit ("ACU") 10. In the layout shown in Figure 1, modules 4b and 4c are adjacent alongside one another. Module 4a is positioned transversely and abuts modules 4b and 4c at one end thereof Apertures in the sides of module 4 a are aligned with a corresponding aperture in the end of each modules 4b and 4e, and allow people to move between modules 4b and 4a (and vice versa) and between modules 4c and 4a (and vice versa), but there is no direct communicating access for people between modules 4b and 4c.

The apertures in the modules are surrounded by appropriate sealing means to effect a substantially air-tight seal, around the apertures, between the modules. Suitable sealing means typically comprise gaskets of elastomeric polymer materials, which are commercially available. In the embodiment shown in Figure 1, the modules are butted together using, inter alia "Egrip", a dimpled silicone rubber material, in combination with a PVC membrane. A door is provided within each module, between the laboratory space 6 and the gowning space 8. In addition, there is a door in the aperture between module 4a and 4b and a similar door in the aperture between module 4 a and 4c. The admin module 4a has a doorway at one end providing access to the gowning area 8a from temporary (e.g. tented) vestibule 12.

There are several important factors which affect the requirements for the air flow and temperature control means of the modular system. These are frequently contradictory, so that a careful balance is required for the system to work as required.

Firstly, it is important to exclude dirt and contaminants, so the laboratory should be substantially air-tight. However, it is necessary to supply a sufficient volume of breathable air to the occupants (generally reckoned to be a minimum of 8 litres per second per person), to allow comfortable working conditions.

Accordingly, it is necessary for the modules to have a good air intake screened by suitable HEPA filters to remove dust, other particulates and potential contaminants.

Being metallic, the walls of the modules have poor thermal insulating characteristics.

As the system may be deployed in hot countries, the interior of the system could become very hot. This tendency is exacerbated by performance of PCR in module 4b, which involves thermal cycling, and heating the samples to temperatures above 70°C.

It is therefore necessary to provide temperature regulation means. In the embodiment shown, this is provided by air conditioning units.

Yet another factor is that it is desirable for the air pressure inside the laboratory to be in excess of ambient atmospheric pressure outside the laboratory: this helps maintain the integrity of the system and reduces the likelihood of the ingress of contaminants.

In particular, it is preferable that the air pressure in the system is highest in laboratory space 6b, since this is the area in which the PCR is performed, and must be kept the cleanest. Tn general, gowning areas 8b and 8c are at an intermediate pressure, and laboratory areas 6c and 6a are at a lower pressure, with the immediate entry to the system, gowning area 8a, being at the lowest pressure in excess of ambient. Thus, in the event that an airborne contaminant gets into the gowning area 8a, there are three increments in air pressure that the contaminant must cross before entering the laboratory space 6b.

The relative pressures and pressure differentials for the embodiment are shown in schematic form in Figure 2. The numbers in boxes represent the desired pressure, in Pascals, in excess of external ambient pressure in the various rooms. The numbers in the large arrows indicate the desired pressure drop across internal boundaries in the system (the point of the arrow pointing to the side with the lower pressure). For simplicity, the gauges (circled A' and B') are shown at the boundaries across which is the pressure differential is being measured, not where they are physically located. By way of explanation, the gauges are actually located in a centralised control box, and are fluidically connected to the air spaces in the relevant rooms by narrow bore ducting. Gauge A is a Magnehelic® Series 2000 gauge from Dwyer Instruments Limited, measuring in the range 60-2000 Pa. Gauges B are flush-mounted Magnehelic® gauges (again from Dwyer Instruments) measuring in the range 0-125 Pa.

Each module has at least one sensor to measure the absolute and/or relative air pressure in the laboratory space and least one sensor to measure the absolute and/or relative air pressure in the gowning space. The relative pressure may be the pressure relative to external ambient air pressure, or may be relative to the pressure in another part of the system.

In addition, the system comprises a plurality of sensors to measure or monitor the volume of air flow through the modules, to check that sufficient air is being circulated to maintain comfortable working conditions.

A communication means 9 is provided between laboratory space 6b and laboratory space 6c. The communication means takes the form of a sealed access way between the adjacent modules, with a hatch at either end, allowing the movement of samples between the respective laboratories. Each hatch is slidably openable, and comprises a transparent viewing port. An interlock mechanism is provided to prevent the possibility of both hatches being opened simultaneously.

Referring to Figure 1 in more detail, a small vent (not shown) in the partition 11 between the laboratory space 6b and the gowning space Sb allows air to bleed from the laboratory space at a sufficient rate to create a pressure in the gowning space which is intermediate between that in the laboratory space 6b of the pre-PCR lab module 4b and the laboratory space 6a of the admin module 4a. In this way, the pressure in the gowning space 8b creates a barrier to the entrance of airborne contaminants from the admin module 4a, whilst the pressure in the laboratory space is 6b creates a further barrier to the entrance of airbome contaminants from the admin module 4a, whilst the pressure in the laboratory space 6b creates yet a further barrier to the entrance of airbome contaminants from the gowning space 8b. In the embodiment shown, the space 6b is designed to retain an air pressure of about 160 Pa in excess of ambient atmospheric pressure, the gowning space Sb a pressure of about 135 Pa in excess of ambient atmospheric pressure, and the admin laboratory space 6a a pressure of about 110 Pa in excess of ambient atmospheric pressure. Excess air in the air flow control system of module 4b is vented to the exterior via exhaust vent 13.

The air flow system in module 4a is essentially identical. A vent in partition 15 allows air to bleed from laboratory space 6a into gowning area 8a. The system is such that the gowning area 8a is designed to retain an air pressure of about 85 Pa in excess of external atmospheric pressure. In this way, the pressure differential between the laboratory area 6a and the gowning area 8a creates a barrier to the ingress of airborne contaminants, whilst the pressure differential between the gowning area 8a and the external environment creates a barrier to the entrance of airborne contaminants into the facility. Again, excess air in the system is vented to the exterior via exhaust vent 17. In each module ducting 28 and air sock 30 provides fresh filtered air to the interior of the laboratory space.

The system in module 4c is slightly different. The majority of the air taken into the module is not fed directly to the laboratory space 6c, but is instead fed into the gowning area 8c, to create a zone of intermediate air pressure (designed to be about 135 Pa in excess of extemal atmospheric pressure). Air in the gowning space 8c bleeds both into the laboratory space 6c and into the admin laboratory space 6a. The air bleeds into laboratory space 6c via a small vent in partition 19, in an analogous manner to the arrangement of vents in partitions 11 and 15. Air bleeds into the admin laboratory space 6a, by allowing a deliberate bleed around and/or beneath the door in the aperture between modules 4a and 4c. Excess air in the system is vented to the exterior via exhaust vent 190 from the laboratory space 6c.

The air flow control means of a single module will now be described in greater detail.

The other modules are provided with substantially identical air flow control means.

Referring to Figure 3, an air inlet 14 is provided at one end of the module. The general direction of air flow through the module is indicated by the open arrows. The air passes through an electrically-powered pre-heater (not shown). The purpose of the pre-heater is to warm incoming air, if necessary (e.g. when the system is deployed in a cold environment), to prevent condensation forming in the filters or elsewhere in the system. The air is then passed through a course double filter 16 to remove relatively large particulate material (e.g. grains of sand). The air is sucked or pushed through a centrifugal fresh air intake fan 18 into a large mixing plenum chamber 20. A high capacity booster fan 22 drives the air through a commercially available sub-assembly, comprising an F5' Bag filter 24 and a HEPA filter 26. There arc various grades of HEPA filter available. The embodiment of the invention described in this example utilises H13 HEPA fihers, which remove at least 99.95% of particles having a diameter of 0.3pn'i.

The air then passes through a relatively large channel cross-section ducting 28, known as the "delivery transformation" and is fed into a diffuser or air sock' 30. This is a porous, synthetic material, which allows the filtered air to be bled into the laboratory space. The diffuser or sock is small enough such that, when positioned against the roof the module, there is sufficient space beneath to accommodate personnel working in the laboratory. The material used for the sock has a permeability selected to allow air to bleed into the laboratory space at the desired rate without allowing uncomfortable drafts, but maintaining the desired pressure in the laboratory space. In the embodiment illustrated, the distribution face of the sock is formed from clean room grade nylon KE0135860, available from ICE Fibertec UK Ltd. (Hampshire, S052 9LP), and has a surface area of about 1.8m2. This material has permeability to air of about 780m3 per square metre per hour at a pressure differential across the diffuser of l2OPa.

Air in the laboratory space is drawn into an inlet 31 on the air conditioning unit 10 by a relatively small fan. The air passes through a heat exchanger and the cooled air is then returned via ducting from the air conditioning unit to the plenum chamber 20 upstream of the HEPA filter unit, where it is mixed with incoming fresh air. The hot is air from the heat exchanger is vented to the exterior via vent 32.

There are various points P1-PlO throughout the air flow control system, indicated in Figure 3 by solid or partially-filled circles, allowing the coupling of remotely-located air pressure monitors (filled circles) or pitot or air foil gauges (partially filled circles) to measure or monitor air velocity. The air pressure gauges or monitors P1-PlO are physically located in a centralised pressure monitor panel 34, allowing all the pressure gauges or monitors in the module to be inspected centrally. Filter switches 35 are provided in connections 33 between certain of the pressure monitors.

As well as the individual air flow control means provided in each module, there is a central pressure monitoring station for the overall facility, as illustrated schematically in Figure 4. The pressure gauges are mounted in a central pressure monitor panel 40, provided in the "admin" module 4a. The panel comprises six pressure gauges; one for each of the three laboratory spaces 6a-6c and one for each of the gowning spaces 8a-c.

The pressure gauges are fluidically connected to the relevant air spaces by polythene or PVC tubing. The monitors in the central pressure monitor panel 40 are passive and purely for information only: they do not form part of any feedback control means to regulate the air flow and air pressure in the modules.

A Dwyer Instruments A414 SS pressure transducer 42 measures the pressure differential between the laboratory space 6b and the gowning space 8b. Identical transducer 44 measures the pressure differential between the laboratory space 6c and the gowning space 8c, and identical transducer 46 measures the pressure differential between the admin laboratory space 6a and the gowning space 8a. A further identical transducer 48 measures the pressure differential between the admin gowning space 8a and the external ambient pressure.

io In-built ducting and easy-connect Camozzi fittings are provided through and/or on the walls of the modules 4a-c, to facilitate rapid fluidic connection of the gauges with the relevant air spaces when the modular system is assembled. Suitable components are commercially available.

Claims

Claims A module for use in a modular deployable system, the module comprising a shelter having external dimensions substantially corresponding to those of a conventional ISO container, the module being adapted and configured, in use, to contain air at a pressure in excess of external ambient pressure, the module further comprising air flow control means including: (i) an air intake; (ii) one or more fans to draw air into the interior of the module; (iii) at least one HEPA filter to filter the air; (iv) a diffuser to deliver a diffuse flow of air to the interior of the module; (v) at least one sensor to measure the absolute or relative air pressure within the module; and (vi) feedback control means to increase or decrease the flow of air into the module based on the output from the sensor (v) so as to maintain a desired absolute or relative air pressure within the module.
2. A module according to claim 1, comprising a plurality of sensors (v), each of the plurality of sensors measuring the absolute or relative air pressure at a respective location within the module.
3. A module according to claim 1 or 2, wherein the feedback control means (vi) increases or decreases the flow of air into the module by causing a variation in the speed of the air intake fan or fans (ii).
4. A module according to any one of claims 1, 2 or 3, further comprising a booster fan (vii) to effect a desired rate of flow air through the module.
5. A module according to any one of the preceding claims, further comprising at least one sensor (viii) to measure the rate of flow of air through the module.
6. A module according to claim 5, comprising feedback means (ix) to vary the rate of flow or air through the module based on the output from the sensor (viii).
7. A module according to claim 6, as dependent on claim 4, wherein the feedback control means (ix) varies the rate of flow of air through the module by causing a variation in the speed of the booster fan (vii).
8. A module according to any one of the preceding claims, further comprising a temperature regulation system.
9. A module according to claim 8, wherein the temperature regulation system comprises an air conditioning unit.
10. A module according to any one of the preceding claims, comprising a plurality of air filters, each filter being associated with a respective audible and/or visual indicator to indicate if the filter requires cleaning or replacement.
11. A module according to any one of the preceding claims, divided into a plurality of rooms by internal partitioning.
12. A module according to claim 11, wherein substantially air-tight doored access is provided between the rooms in the module.
13. A module according to claim 11 or 12 wherein, in use, a pressure differential exists between the plurality of rooms within the module.
14. A module according to any one of the preceding claims, comprising a sensor to measure the external atmospheric pressure, which sensor is exposed or fluidically connected to the atmosphere by a conduit or fluid-communicating bore which rises above the exterior of the module.
15. A module according to any one of claims 3-14, as dependent on claim 2, wherein a visual indication of the absolute or relative air pressure measured by each of the respective sensors is given at a central monitor panel in the module.
16. A modular system, comprising a plurality of deployable shelters in accordance with any one of the preceding claims, the system forming a multi-roomed facility in which, in use, the air in at least one of the rooms is maintained at a pressure in excess of ambient atmospheric pressure and/or in excess of the atmospheric pressure in an adjacent room.
17. A system according to claim 16, comprising a plurality of rooms, and wherein a pressure differential is maintained between the different rooms.
18. A system according to claim 17, wherein the different rooms are in the same module.
19. A system according to claim 17 or 18, wherein the different rooms are in different modules.
20. A system according to any one of claims 17, 18 or 19, comprising a plurality of pairs of adjacent rooms, and a pressure differential is maintained, in use, between each of the adjacent rooms in the pairs.
21. A system according to any one of claims 17-20, in which, in use, a pressure cascade is maintained between a room with a highest internal pressure, one or more rooms having an intermediate internal pressure, and a room having a lowest internal pressure, which lowest internal pressure is still in excess of external atmospheric pressure.
22. A system according to any one of claims 17-21, comprising a communication means between two adjacent rooms of the facility, which communications means allows the physical transfer of samples from one room to the other, but which is too small to allow the movement of people between the rooms.
23. A system according to claim 22, wherein each end of the communication means comprises an operable hatch or cover, to allow samples to be delivered into, or recovered from, the communication means, and further comprising an interlock to prevent both hatches or covers being open simultaneously.
24. A system according to any one of claims 17-23, comprising a plurality of pressure gauges and/or air flow gauges centrally located in a single module and which allow centralised inspection of the pressure and/or air flow rates at different, remote locations, typically at different modules, within the facility.
25. A method of making a module according to claim 1, the method comprising the step of assembling, in functional co-operation, each of components (i)-(vi) in a single module.
26. A method according to claim 25, performance of which results in manufacture of a module in accordance with any one of claims 2-15.
27. A method of making a modular system according to any one of claims 16-24, the method comprising the steps of: (a) deploying a plurality of modules in accordance with any one of claims 1-16; and (b) forming a substantially air tight access-way for personnel between at least two of the plurality of modules.
28. A method according to claim 27, further comprising the step (c) of forming fluidic connections between the plurality of modules to facilitate remote monitoring or inspection in one module of the air pressure and/or rate of air flow in another module.
29. A module substantially as hereinbefore described and as shown in the accompanying drawings.
30. A modular system substantially as hereinbefore described and as shown in the accompanying drawings.