Decontamination shelters have evolved to keep pace with potential threats and to extend the range of applications. It is important to make the right choice of ancillary equipment as well as the shelter itself to ensure optimum performance and maximum flexibility.
Image: Decontamination Shelters
Responding to a Chemical, Biological Radiological, or Nuclear (CBRN) incident invariably means providing some form of decontamination. As the potential threats increase and the hazards faced by the emergency services grow ever more complex, manufacturers of decontamination equipment have responded with a choice of solutions and specialist equipment optimised to suit specific applications.
Saving life is always the priority and therefore a prompt response is essential. Decontamination involves washing potentially harmful substances from the body, and for emergency service personnel this may also include protective clothing and equipment. In principle, the process is straightforward and involves the use of a shower, either fixed or hand-held.
Developments in Detergents & Chemicals
Adding detergents and other chemicals to the showering water may help to speed up the removal of specific contaminants or simply improve the overall effectiveness of showering. With traditional detergents and chemicals used for decontamination the emphasis has been on high dilution combined with soap/detergent solutions that in some cases can be a problem with insoluble contaminations. To address this problem with more practical knowledge and collaboration with chemical specialists and the introduction of new protocols, manufacturers can offer a more targeted approach. This can reduce run off waste by 90% and reduce time by 50%.
Image: Decontamination Shelters
Development of Decon Structures
Speed of deployment is obviously critical in emergencies, so weight, portability and ease of erection are important considerations. Stability is also essential together with a high level of reliability. Shelters need to be able to withstand repeated use in harsh conditions, during training and actual deployment, without sustaining damage that would take them out of service for repair.
Early shelters focused on the needs of the emergency services, providing a portable showering system that could be quickly erected at an incident and used to remove contaminants from protective clothing and equipment.
As the threat from terrorism intensified, attention focused on mass decontamination and the possibility of having to treat hundreds or even thousands of casualties in the shortest possible time. In many instances, at least initially, this was achieved by simply scaling up the emergency units.
Manufacturers then addressed the specific needs of decontaminating large numbers of the public. Multiple channels through the shelter mean that male and female casualties can be treated simultaneously, passing along parallel channels separated by modesty screens. The internal partitioning in any shelter should be easily repositioned to ensure maximum flexibility – for example, providing separate channels for walking and stretcher-borne casualties. Different authorities have their own preferences based on local conditions, cultural needs and the nature of perceived threats, so this level of flexibility is essential for any type of shelter. Increasing the size of the shelter also provides additional space to accommodate two- and three-stage decontamination where the addition of chemicals and detergents to the initial wash water can improve its effectiveness.
Decontamination shelters are either inflatable or have rigid frames. For both, the emphasis is on stability, durability and speed of deployment. The end use remains the same; it is the materials and construction that make the difference.
Shelters, such as the Hughes’ Cupola range, consist of an inflatable frame with removable lining forming a stable and durable structure that is easy to erect. For safety an inflatable frame shelter should incorporate several separate sections so that, if it is accidentally punctured, the structure will not collapse on casualties or emergency service personnel. It is the same principle that applies to the design of life rafts and inflatable boats. Extensive testing has also revealed that contrary to what might be expected, glued and taped joints are far more durable and easier to repair than welded joints.
A mobile infection control unit incorporating chemical additives in the shower
Image: Decontamination Shelters
The ability to anchor the unit securely is also an important consideration as it may have to be used in adverse weather conditions. Although stability is the result of good design it also depends on the provision of secure anchoring points around the shelter so that it can continue in use during strong winds. The simplest and most effective is often strategically positioned guy ropes attached to the inflatable frame and secured by stakes driven into the ground.
Effective containment of contaminated wash-off is also important. While requirements relating to discharge into sewers will vary depending on local regulations, good practice dictates that all shelters should provide some form of sump to store the waste water until it can be collected and safely disposed of. With inflatable shelters this can be supplied as an integral part of the base of the unit so that when the shelter is inflated it is already in place.
Raised flooring is necessary, allowing water to drain through into the sump and prevent casualties standing in potentially contaminated wash off. This is invariably made from interlocking non-slip modular panels, in part for ease of storage and transportation but also to accommodate different shelter sizes and configurations. Ideally, all shelters, inflatable or rigid framed, should be positioned on level ground. In practice, however, this is not always possible, and working on a slight incline can soon raise the level of water at one side of the shelter above the top of the floor panel. When approaching suppliers, it is therefore advisable to seek out the deepest possible floor panels to take account of any variations in water depth in the sump.
Rigid Frame Shelters
Although this type of shelter in various forms has been in use for a while, concerns have been expressed about portability, ease of erection and long term durability. Versatility is also increasingly important as emergency services try to maximise their investment in shelters to accommodate the growing range of applications. It is not economically viable or logistically desirable to carry a multitude of bespoke shelters.
A typical rigid frame emergency response shelter
Image: Decontamination Shelters
The latest generation of rigid frame shelters, such as the Hughes’ Articulating Rapid Deployment (HARD) Shelter, successfully addresses these issues. Now, with no need to compromise, rigid shelters are becoming the preferred choice.
Firstly, lighter and stronger materials are used. In the shelter, the T6 aluminium frame is derived from materials used for mountain bikes, giving exceptional strength for its weight and good shock resistance. Neoprene-coated Nylon for the shelter covering draws its superior properties from many years research into lightweight water-proof clothing. The result is a lightweight shelter that is easier to transport and assemble, robust enough to withstand rough treatment, even in the most testing conditions, requires minimum maintenance and lasts longer.
Ease of assembly is critical. The Hughes solution, for example, employs a single articulated frame that two people can erect and have ready to use in just two minutes.
If a rigid frame system as well as inflatable has an interchangeable liner this immediately extends the range of applications. With one standard shelter and a selection of liners, users can easily switch applications from decontamination shower to forensic examination tent, command and control facility or even a field mortuary. Insulation can increase the versatility even further, ensuring the shelter is equally effective in extreme climates. Depending on the application, air conditioning is also an option worth considering particularly for hot climates and when the unit is used as a temporary mortuary.
Whether opting for an inflatable or rigid frame system, it is important to choose a range of ancillary equipment that will optimise performance, extend the range of applications and provide a measure of self-sufficiency that may be critical when working in remote places.
Understandably, the generator is often the first piece of ancillary equipment that operators consider.
Ideally, all electrically-powered equipment should have a ‘low energy’ rating. Reducing the power consumption of ancillary equipment such as lights and pumps has led to the use of smaller generators ranging from 2kW to 6kW depending on the load. In addition to energy savings, generators can be smaller and lighter making them more manoeuvrable, quicker to deploy and easier to transport, especially by air. A further development is the availability of flexible solar panels that can be fitted to shelters when they are used over longer periods, such as in search and rescue operations.
A mobile air conditionaing unit can enhance and extend the performance of shelters
Image: Decontamination Shelters
However, such reductions must not be at the expense of endurance and reliability, which is particularly important in remote locations. The size of the fuel tank on the generator can be significant and best practise suggests an ideal capacity to give at least eight hours of uninterrupted power supply.
High quality lighting inside and in the immediate vicinity of the shelter is also essential for efficient and safe operation and ensures that it can be used on a 24-hour basis. Externally, low energy flood lights are the ideal choice and these can usually be supplied on telescopic columns to provide sufficient height for directing the light to flood the working area. Also consider lighting with battery back-up, as this offers even greater flexibility and a measure of independence from the generator. In addition to external lighting, this type of light can provide sufficient illumination for the interior of shelters if they are fitted with a white translucent cover. It is something to keep in mind when discussing requirements with your shelter supplier. Shelters with darker covers, such as military camouflage, will, of course, need additional interior lighting units which, on rigid shelters, are normally clipped into position on the overhead frame.
Breakthrough in Portable Air Conditioning (AC) Units
It is important to maintain an acceptable temperature and air quality within the shelter or decon system. To some extent this will depend on the external ambient temperature range, but the role of the shelter is also an important factor. The temperature for a temporary mortuary, for example, should be no more than 4C and a shelter used for decontamination may need forced ventilation to stop dangerous gasses or vapours building up inside.
New lower energy mobile ac/heaters can be positioned alongside the shelter to feed temperature-controlled air through a recirculation flexible ducted system. This can be either cool air for hot climates or switch over to heated air as required.
New Levels of Containment
Emergency decontamination showers obviously require a water supply and way of removing the wash water. Low energy pumps are available to transfer the water to and from the shelter. Portable heavy-duty reservoirs can provide temporary water storage for showering, while contaminated clothing, equipment and waste water is best stored in collapsible palletised receptacles that can be transported by pallet truck and then stored flat taking up minimum space on rescue vehicles or in the warehouse. For the reservoirs, 5000 litres or 6000 litres are a practical capacity.
As already discussed, the use of chemical additives to the water can significantly improve the efficiency of decontamination showering and has the added advantage of reducing the amount of water required. The resulting reduction in waste water volumes opens up the prospect of more efficient methods of waste management by using environmentally beneficial filtration or recycling techniques.
While considering the merits of inflatable and rigid frame shelters, it is the availability and suitability of ancillary equipment that may eventually determine which route you take. With the latest technology and the benefit of user feedback, manufacturers have refined their products to provide a much more targeted approach that delivers optimum performance for specific tasks while retaining flexibility in deployment to enable you to make
the most of your investment.
Andy Whitehead is Decon Manager at Hughes Decon Systems
For further information, go to www.hughes-safety-showers.co.uk