6 Technical rooms
6.1 General requirements for technical rooms
Technical rooms group the equipment for centralised services in buildings like heating, ventilation, air-conditioning (HVAC), data, telecommunication, hot water, fire prevention, electricity supply etc. This chapter will only treat technical rooms for HVAC and hot water applications.
There are many requirements for technical rooms, and often, when e.g. safety, ecology or energy performance is involved, those requirements are described in standards and norms. It is not intended to describe all worldwide, European or national standards in this document, but to give an overview of the different aspects that need attention when designing technical rooms for HVAC and hot water production.
Accessibility
Technical rooms need to be accessible for people and for the replacement of equipment. The complete access path from outside (street level) to the inside of the room needs to be wide enough to enable replacement of the biggest component with an expected lifetime that is shorter than the building's lifetime. It is highly encouraged to have elevator access to the level of the technical room for easy transport of big and heavy components.
Space
Technical rooms need to be large enough to place all the required equipment, but also to install (this depends on the present sizes of the entrances in the room) and to maintain this equipment. In the Renewable Energy House the installations were placed in the cellar (Figure 79), where the installation and the ducts were integrated in the room with respect to the architectural aspects.
Figure 79: Technical room in cellar of the Renewable Energy House
More information about space requirements in function of envisaged technologies can be found in the further this chapter.
Position
Almost all technical rooms need one or more connection with the outdoor. Those connections can be ventilation grids, chimneys, ducts for air or liquids, electric cable transfer or openings to bring in large equipment directly without having to pass through the building. The most critical interface with the outdoor is for the ventilation system. In case of balanced ventilation, sufficient distance between the air inlet and outlet should be foreseen. Fresh air ventilation grids must be placed where no polluted air can be found.
The position of technical rooms with centralized hot water production should be as close as possible to the hot water drawing points. If the distance of the distribution is too long, a recirculation needs to be foreseen because of the legionella risk (standards and local regulation have to be followed). Measurements show that thermal losses of such a recirculation can be higher than the actual hot water demand, so the length of the complete distribution circuit needs to be minimised. An alternative solution is to foresee a hot water storage system on another, more central place than the main technical room. The position of the technical room (or the hot water storage system if present) and the insulation level of the ducts are two important parameters to reduce the thermal losses.
Generally boiler rooms are placed on the highest level, even in renovation, to avoid long chimney and fire resistant duct from downstairs.
Fire safety
The boiler room must generally be separated from other technical rooms. Boiler rooms must reach a fire resistance degree according to standards and all the openings coming in the boiler room, such as pipes, electrical cables etc. must be closed according to special fire resistance requirements.
If gas is used as primary energy, gas detection devices must be installed in the boiler room, to signalize any gas leakage and to stop electricity and gas supply.
For other technical rooms, such as the ventilation room or cold production room, specific requirements must be followed. Generally there is no prescription to have separated rooms for each type of technical room, apart from the boiler room.
Noise
Air treatment groups and cooling machines are a source of noise, and therefore the room where they are placed has to be treated. To obtain good vibration insulation, the equipment must be separated from the concrete structure with high efficiency shock absorbers, which reduce up to 90-95% vibration intensity. When the insulation is not enough, a second concrete slab must be placed, separated from the first one with shock absorbers. To apply this solution, the resistance of the existing slab must generally be reinforced with additional steel structure.
Services
Technical rooms generally need electricity supply, a connection to the water circuit and to the sewers. The electricity supply is preferentially done with triphased alternating current. Generally each technical room has one or more electrical board, for example one for cold production and one for ventilation. The boiler room has a separate board. The supply of the cooling machine is done directly from the general electricity supply room of the building.
In case of boilers with open combustion, a correct natural ventilation supply needs to be planned to ensure sufficient fresh air for the combustion process and the draft of the chimney. Other technical rooms also need a minimum natural ventilation.
6.2 Planning technical rooms in function of envisaged technologies
Mechanical ventilation
Mechanical ventilation systems come in different shapes and with different functionalities. To give ideas about the required size, an air treatment group of 10 000mł/h requires a room of 7x3,5 m˛. The grid section for each grid is about 1.2m˛. For an air treatment group of 20 000mł/h, a room of 9x4m˛ is required. These values are very rough first indications and shouldn’t be generalised. If no room with sufficient size can be found, it could be possible to put the air handling unit outside, e.g. on a flat roof (rooftop units). The units (inside and outside) need to be accessible for maintenance.
Boilers
If combustion boilers are to be foreseen, the chimney is often an important criterion for the technical room selection. The European norm EN 1443 describes chimney and ventilation requirements to provide enough combustion air. In case of fuel or pellet fired boilers, a connection with the storage has to be foreseen. To give an indication on the required floor space for pellet boilers a typical floor space of 2x2.5m˛ is needed for boilers <100kW [FOR08]. Normally, additional space needs to be foreseen for maintenance and installation.
Solar thermal system
Beside ventilation groups, solar thermal systems are often the largest components in technical rooms because of the storage tanks. The needed floor space depends on the total storage volume, height and number of the tanks. General rules are difficult to determine.
Heat pumps
Heat pumps come in many different forms and applications, general rules are difficult to give. Unlike boilers, no chimney or connection to fuel or pellet storage is needed.
Chillers
Chillers come in many different forms and applications, general rules are difficult to give. Rooftop chillers can be an option if there is not sufficient space in the technical room(s).
Electrical boards, regulation and control
This equipment is not taking much space, although it cannot be omitted in the technical room design.
6.3 References
[FOR08] http://www.forever-fuels.com/files/u8/FFdesignguide.pdf