Air hygiene for offshore
oil and gas industries improves the health of employees by effectively destroying micro-organisms which build up in air conditioning systems through UVC and air oxidation. Effective
UVC systems prevent health issues accruing in employees by providing air quality in accommodation rooms, offices and recreational areas.
While there are many different companies offering similar systems with the same benefits it can become a daunting task to appoint which system is best for you, your business and employees health. This article focuses on the issues that develop in offshore oil and gas systems particularly in heating, ventilation and cooling systems which then causes health problems among staff, we then look at the solutions and benefits of using UVC.
Advanced Air Hygiene state that their effective UVC and
air oxidation will improve the air quality in HVAC systems. Below are the areas which are affected most by contamination:
Return Air and Fresh Air Mixing Chamber
Pre Filter and Mixing or Bag Filter
Cooling Coil Section and Drain Pan
Supply Air Ducting (From The AHU to the conditioned rooms)
Occupied Rooms
Return Air Ducting (From the conditioned Rooms to the AHU)
Return Air and Fresh Air Mixing Chamber
This is where the contaminated air returns from occupied areas which may contain viruses and bacteria. The fresh air may also be contaminated depending on where it has come from, but will most certainly contain particulates.
Pre Filter and Mixing or Bag Filter
Filtration is essential in any HVAC system to stop particulates. The normal system would have an F7 pre and bag filter. The bag filter is designed with concave chambers to increase the surface area so that the capacity of the filter to hold particulates is increased. The Filter density can be increased to HEPA which will filter very small particulates and some microscopic pathogens. Increasing filter density will increase the pressure drop within the system which in turn will increase the load on the Fan and therefore, increase the running cost of the system. Some HEPA Filters are impregnated with disinfectant but this can degrade very quickly in adverse conditions such as High Humidity.
The filters do not kill living organism which in fact double every 4 hours with viruses doubling every 2 hours. Due to the conditions within the cooling coil, chemical cleaning is not an option and will not prevent the increase of microbial colonies.
Cooling coil section and drain plan
This is where the main cause of air pollution occurs within the HVAC system. Again chemical cleaning is not an option due to conditions within the cooling coil and the regularly this would have to take place to be effective.
UVC emitters should be fitted across the cooling coils which will then emit continual dose of light. Because the cooling coil is in a fixed position, a low amount of UVc will produce a large dosage over 24 hours. This will keep the cooling coil completely free of Bio-Film which in turn will significantly improve the general air quality.
Cooling coil without UVC
Cooling coil with UVC
Over the past 5 years air oxidation has been developed to operate in high volume HVAC systems which you would find in the oil and gas industries.
Supply Air Ducting
a) A UVc Duct Module should be fitted into the discharge ducting. This can be either by a large plenum installed in between the AHU and the first division of the ducting or a number of smaller UVc Modules installed in each ducting leg. The most important point to understand when employing this method is that the UVc emitters must run in line with the duct. The Dosage of UVc applied must be calculated based on the size of the duct in section and the speed of the air as it passes through the duct. By offering the UVc emitters to run along the length of the duct we can ensure that the air is exposed to the UVc for as long a time as possible. b) When it is not possible to find the space for a UVc Duct Module or for a retro-fit, we can use Advanced Oxidation Probes to achieve the result.
Typical UVc Duct Module
Occupied Rooms
In sleeping quarters a build up of viruses and bacteria occurs often and can be prevented by utilizing of the Air Treatment as described above. In Modular Accommodation the deployment of a standalone UVc Air Disinfection Unit in each room will solve the problem.
Return Air Ducting
If it is not possible to deploy either UVc modules or Advanced Oxidation probes in the supply air ducting for occupied rooms, a reasonable alternative would be to fit UVc or Advanced Oxidation Probes into the return air duct. This method alone will not improve the general air quality without treatment to the cooling coil but it will prevent cross contamination by eliminating the Viruses before they can get into the supply
air system.
For more information on UVC, air oxidation and air hygiene systems please visit
www.aahygiene.com
