Hoping for rain at Wimbledon

24 June 2009

Only a spell of typical Wimbledon weather will finally prove that the ventilation systems that operate when the new roof over Centre Court is closed will be able to cope with the expected humid conditions. Tests on the performance of the roof used testing equipment supplied by BSRIA Instrument Solutions and the chillers are by Aermec.

This year’s Wimbledon Championships sees the first use of the new retractable roof over Centre Court. Hailed as a major engineering feat, the roof is designed to be deployed in poor weather conditions to ensure continuity of play. However, equally important is the new air-management system, which has a vital role in maintaining good court surface conditions. Whilst the personal comfort of the audience is important, humidity is a serious issue, with excessive moisture leading to the risk of slippery grass. The main source of humidity is latent heat from spectators.

Nine Aermec RV 3603E chillers each with a capacity of 850 kW have been installed. Capable of handling 27.3 litres of water a second, the chillers are key in helping to maintain a 50% relative humidity with the roof closed. Each chiller is equipped is equipped with Aermec’s Remote Monitoring, Control and Reset system (ROMEO) enabling 2 way communication via mobile phone between the chillers and the engineers, who will man the chiller farm throughout the tournament.

From BSRIA e-newletter published in June
One of the concerns expressed over the 'cover up' at Wimbledon's Centre Court was that the ventilation for the playing surface, for the stadium bowl or for the roof structure might prove ineffective. The testing time came on Sunday May 17th when Tim Henman and Kim Clijsters, Andre Agassi and Steffi Graf gave a capacity 15,000 Centre Court crowd and an even larger television audience a full afternoon of high quality tennis and excellent entertainment with the new roof closed against the showers that kindly appeared on cue. Both the crowd and the players agreed that conditions were excellent in the enclosed area; no trace of sweating on the grass, comfortable conditions in the seating areas and no condensation forming on the inside of the 5,200 square metres roofed with the translucent, waterproof, strong and flexible Tenara fabric.

Approval of the ventilation at the dress rehearsal of the new Centre Court was virtually unanimous and congratulations to the Main Architect Populous, and M-E Engineers who were responsible for the mechanical and electrical design of the engineering systems within the bowl,
The new roof at centre courtrained in. Nevertheless personal plaudits for innovative construction projects must always be backed by scientific proof. To test the air management in the closed Centre Court, the Championships' Committee of Management called on BSRIA Instrument Solutions for the necessary testing equipment, and on Balcomm Limited and Skanska Rashleigh Weatherfoil for the expertise to use it to best effect. The testing programme started long before the demonstration matches took place and this included the use of smoke generators to make the air distribution patterns visible within the court.

Particularly important was the viewing of the airflow patterns from the high velocity jets that prevent condensation at roof level and initiate air distribution from the nine chiller units that supply 143,000 litres of conditioned air per second into the enclosed space, keeping humidity low and therefore the famous Wimbledon turf free from moisture. For the great day itself, when the effects of a full capacity crowd on ventilation patterns could at last be measured, BSRIA Instrument Solutions provided temperature and humidity data loggers to monitor the minute-to-minute changes throughout the playing and viewing area and particularly checking the effects of the heat generated by a large and excited audience. Two loggers were placed on the umpire's chair and there was even one in the Royal Box to make sure that no-one was left out.

Smoke test with the roof closed to demonstrate airflowThe detailed data obtained from the BSRIA equipment is still being evaluated but there seems no reason to doubt that both the design and installation of the air distribution systems came through the tests with flying colours. Certainly the players were happy with the court conditions. In particular Tim Henman [who is a member of the All England Club's committee of management], having admitted initial misgivings of the effect of roof closure on the turf, was delighted with the result. "It's a pretty miserable day outside" he said "But it's just the most fantastic playing conditions here. No moisture on the court, no losing your footing and a fantastic atmosphere with the roof keeping the noise in."

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