6.6 Other Building Services

Other main servicing considerations linked with daylighting are described here. Fig.6.6 summarises the main points to be considered.

6.6.1 Ventilation

Air supply for a space is very important, in terms of air quality for the occupants and controlling humidity and temperature levels for the preservation of the building fabric. In the traditional, mechanically ventilated sports hall, a large amount of energy is used for providing ventilation; 11% for a typical dry sports centre.⁴⁸ The energy includes the electricity for driving fans and the heating or cooling energy required to maintain the ventilation supply conditions.

Effective ventilation savings can be made through the use of heat recovery, heat pumps, air recirculation (minimum fresh-air) and variable speed fans. However, the most efficient ventilation method is to naturally ventilate, if possible.

6.6.1.1 Passive Ventilation

A natural ventilation strategy can be successfully integrated into a daylit hall, by the use of the windows, doors and other openings. Various methods exist to naturally ventilate a space, including:

These methods rely on factors related to the building’s design:

The stack effect uses the vertical temperature difference in a space to drive the warm stale out at the top and draw fresh, cooler air in at the bottom. This can be exploited in a sports hall using opening rooflights and doors or louvres at ground level to control air flows. Care needs to be taken with the air velocity in the space, ensuring that it does not exceed 0.1 m/s. Low air velocities are paramount in sports halls, especially where badminton is played, as the shuttlecocks can be easily disturbed by air flows.

Cross-ventilation relies on there being external openings on opposite sides of a room; using pressure differences between facades to drive air through a space.

Wind driven ventilation is linked to cross-ventilation, as it uses the wind pressure differences to drive it (there being positive pressure on the windward side and negative pressure on the leeward side of a building). However, some forms of ventilation exist where the speed of the wind over a cowl or turret can draw out stale air from a building. This form of ventilation is reliant upon there being sufficient wind to drive the system, and so may not be totally reliable, especially on hot, still summer days.

It is often found that combinations of these three main types of ventilation are used to give reliable ventilation rates during most weather conditions. Wind driven turret ventilators can also be used as stack extract terminals and, if correctly positioned relative to inlets, also provide inlets or outlets for cross-ventilation.

The main interaction with daylighting is through the integration of control of ventilation through opening windows. Depending on the layout of the building it may be preferable to use one or a variety of the natural ventilation types - provided that they can provide low air velocities.

6.6.1.2 Mechanical Ventilation

Mechanical ventilation systems do not have significant effects on the design for daylighting. However, if there are heat gains in the hall from windows there may need to be mechanical ventilation to cool the hall. This can be achieved through simple extract fans, or a more complex ducted system, with heat recovery. Natural ventilation should be encouraged wherever possible.

6.6.2 Heating and Cooling

The heating of a sports hall can be by a range of mechanical or passive means; radiant, conductive or convective. Daylighting provides the opportunity to heat the hall by the admittance of solar energy through the glazing. This can lead to overheating, where solar gains are uncontrolled. However, if the gains can be usefully controlled, they can heat the sports hall and adjacent facilities when required.

Click HERE to view Fig. 6.6 - Checklist for the Interaction of Servicing Strategies with Daylighting

The main heating requirements of sports halls are in the winter, though poorly insulated halls may require additional heating in the autumn and spring. The solar gain, therefore, has to be capable of being used in the winter and excluded for most of the rest of the year. This leads to conflicts in design and operation and needs to be carefully designed. Summer overheating will be the main problem associated with significant quantities of southerly orientated glazing.

North facing roof glazing, preferable for providing natural, glare free lighting, does not add to the solar gains of the space and may even cause heat loss unless significantly high insulation levels are provided. However, northlights will give an opportunity for cooling, if required. Opening rooflights can be used to create a stack effect, if air is drawn in through low level openings and out through the roof.

The requirement for heating, even if a hall is carefully designed, will be necessary especially in the winter. There will probably be a need for a mechanical system of some form; pumped water circuits. A mechanical heating system will not have profound effect on the daylighting scheme, unless the heat emitters obstruct any windows, such as high level radiant panels.

Mechanical cooling is not a requirement for sports halls. Very few have been designed where there have been chillers or other cooling systems specified. Most cooling requirements can be met through ventilation.

6.6.3 Acoustics

The acoustic qualities of a sports hall are important, as people, such as coaches, need to be heard clearly. The daylighting method may have an effect on the acoustics. For example, large areas of glazing, can create problems with harsh acoustics or echoes. Areas of acoustic absorption designed into the structure may adversely affect light levels by their lack of spectral reflectivity.

Generally, a reverberation time of no more than 2 seconds should be designed for. If the space is too dead, acoustically, then voices will be absorbed too quickly and people will have difficulty hearing. Noisy sports, such as basketball, will sound even louder if there are no absorbent surfaces in the hall.

6.6.3.1 Noise Source

Sports halls are often designed as multi-purpose spaces; catering for a variety of sports and social functions. Whilst general sports are not excessively stringent on noise levels produced by plant and external sources, badminton, other quiet sports and concerts tend to require stricter noise ratings. Generally, noise levels of NR 30 to 40 are considered acceptable for sports halls.⁴⁹

6.6.3.2 Construction

The acoustics of a space are largely governed by the dimensions and construction materials. Sports halls are generally constructed from either steel frames with block work walls; timber frames; timber cladding; concrete and or metal cladding. There will also be areas of insulation, but these are usually hidden behind the internal walls to avoid damage. It is the combination of these elements; their ordering and their dimensions that can have a beneficial or detrimental effect on the acoustics.

Halls need to be large enough to accommodate the dimensional requirements of the sport being played in it. For example, badminton halls should be greater than 7.6 metres high, and wide and long enough to allow space for the desired number of courts plus circulation space at the edges. The space requirements for individual sports are listed in appendix C.

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