A New Concept in Pitch Covers
I recently visited West Hill Park School on the outskirts of Southampton to view what had been billed as a totally new concept in pitch covers. They are designed and built by Banks Specialist Covers who have been manufacturing a variety of covers including tension covers over stands for the last ten years. At the demonstration I met David Banks who is the Managing Director and
Editor: David, what gave you the original idea to design this cover?
David: I was at a meeting with one of my customers, Phil Harper the agronomist, discussing an order for frost covers and the conversation came around to what he really needed was a removable greenhouse to protect the grass from the elements and allow it to grow in the Winter.
Editor: Where did you get the idea for the concept?
After this initial meeting I looked at all the different covers which were currently on the market and asked Phil to give me all the good and bad points of each cover and a wish list of all the important points that he would like to see in a cover."
Editor: What was your design criteria?
David: The cover had to be able to be deployed and recovered very quickly, certainly in well under an hour with a maximum of two men and allow the ground staff to carry out a full maintenance programme underneath it.
Editor: How would you describe this type of cover?
David: The cover is a fully pressurised air dome which is attached to the ground around the base and is held up with air pressure underneath the fabric, similar to the permanent air domes used for indoor tennis courts and swimming pools but our fabric weight is only a fraction of what is normally used.
Editor:This cover is vast, how have you been able to make it out of such lightweight material?
David: The material is light and incredibly strong but we do not rely on the material strength alone. The cover is attached to the ground every 7 metres. From these points webbings are attached to the skin of the cover and the skin load is transferred into the webbings. The cover has been structurally engineered and we know the loads at any given point for any given wind speed.
Editor:A normal air inflated building is continuously bolted to the ground to seal it from air loss. You have just said that your cover is held down every seven metres, what is stopping the air from escaping?
We had to be able to install and remove the cover very quickly which meant the cover had to be self sealing to the ground. The cover incorporates a skirt that sits on the ground and as air passes underneath the skirt the differential in air pressure sucks the skirt onto the ground creating a seal. So in reality the cover is not totally sealed. This is actually a positive advantage to the environment inside the cover because you need to keep changing the air.
Editor:The loads on the webbings where they are attached to the ground must be incredibly high. What type of foundation is needed to hold the cover down?
David: Depending on location the loads vary from about 2 to 12 tonnes. We use a ground
Editor:How many sections does the cover come in and how is it deployed and recovered?
David: Our cover is one piece to achieve the speed required with only two staff. As the material is so light and flexible we are able to wind it on to a small drum approximately 8 metres long. The drum is powered from the tractor pto and the cover is guided on to the drum with a couple of roller fairleads. The drum sits on a trailer for transport on and off the pitch.
Editor: Can the cover be customized to suit particular requirements?
David: All our covers are individually made so they exactly fit the pitch. As long as it is within the constraints of the design we can incorporate almost all physical requirements. The cover can be almost any colour and we can brand it with sponsors logos if required.
Standing inside the cover you can feel the heat from the sun.
David: As long as you have direct sun light on the cover the air will heat up exactly like a greenhouse. The material also gives a light permeability of 70% in the natural colour.
Editor:When there is no sun how are you heating the air?
David: A gas burner is the simplest way, but for every litre of gas used you produce a litre of water which will increase the humidity fairly quickly. We offer the fans with electric elements built in which produce a dry heat. The final decision is with the ground staff and will probably be a combination of the two to cope with severe weather.
Editor: Are there any problems using a tractor inside the cover?
David: The air volume inside the cover is vast. However, we have the ability to change the air up to twice an hour so there should never be a build up of exhaust fumes.
Editor:The cover is going to provide a perfect environment for disease to multiply.
David: This is outside my experience but I understand it can all be controlled with the right chemicals and I am sure Phil Harper will be very happy to advise on the matter. Also because the cover is quick to deploy and recover, it could be removed for part of the day between showers.
Editor:How long will the demonstration site be available?
David: We have a good relationship with the school and I hope it will be available until the end of April.
For further information on the Banks cover or to arrange a demonstration visit please phone David Banks on 01489 582444 or e-mail firstname.lastname@example.org