Hospitals require a number of potentially hazardous chemicals in day to day maintenance, cleaning, sterilisation, testing and operating applications. The health care sector represents one of the largest users of chemicals in the UK. The storage of these chemicals involves a number of considerations in terms of temperature, ignition control, ventilation and segregation. In this article, we focus on chemical storage ventilation.
The ventilation of chemical storage areas is of paramount importance to ensure clean air and a safe environment for staff, visitors and patients. Ventilation is needed for chemicals and their containers as they have the potential to release dangerous quantities of vapours or gases that are damaging, flammable, corrosive, irritating or toxic. Well ventilated storage is particularly key for those substances classed as fuming or highly volatile. It is recommended that such ventilation be by air extraction from the storage room or cupboard to an external exhaust at a safe distance from any openings (windows or doors) back into the building.
The fume extraction system needs to be suitable for handling air that is potentially corrosive, given the nature of the chemical vapours to be carried from the storage area. Axair Fans offers a range of fans designed specifically for extracting corrosive air in chemical storage ventilation applications, due to their polypropylene construction. In addition to standard corrosive fume extraction, Axair also provide polypropylene fans suitable for ATEX Zone 2 applications. These applications will have been assessed by an official ATEX specialist and deemed to have a risk of the accidental presence of explosive fumes.
In such chemical fume extraction systems, it is best practice to site the fan at the end of the ductwork system. The reasoning behind this is to keep the ductwork under negative pressure which means, in the event of a leak, the system would draw in clean air rather than blowing out fumes into the building. This would limit any damage caused by the leak before it was identified. See our page on understanding fume extraction systems and components to learn more.
In order to accurately specify a fan for chemical storage ventilation, there are two key pieces of information required; the airflow rate and the system resistance. Airflow rate is be based on the number of air changes per hour needed in the storage area. This figure is usually specified by the consultant or the hospital. From the airflow rate, the size the ductwork is determined and so the system resistance is calculated. There may be a requirement to control the fan with a sensor to switch the fan on and off. This can be achieved with the use of an inverter. The sensor sends a signal to the inverter, which in turn controls the power source to the fan.
Please note that if there is a possibility the installation needs to be ATEX rated, then an expert needs to determine the Zone classification for the area. The information they provide will cover the size of the Zoned area and the standard of equipment to be used in the Zone. See our ATEX page for more technical information on zoning and specifying.
For further information or to specify a solution for a chemical storage ventilation or fume extraction application, please contact us on 01782 349 430, email firstname.lastname@example.org or see our chemical fume extraction page.
View our fume extraction brochure for more details.