Engineering Services
for
Buildings
By J. N. Buss,* MIHVE, MASHRAE
T KEEP ABREAST of present day development, the engineering services for buildings are becoming more complex and extensive and it is essential that they are planned to be efficient in operation and economical in space utilisation. The present trend in building design is towards an exactness of space allocation and this necessitates that, in the initial stages, proper account is taken of the en- gineering services.
Too many cases occur where a building is architectually planned in great detail and only then is con- sideration given to the services. The result of this system can only be a compromise of services and building which in turn results in higher capital and operating costs for the building
owner.
To ensure a successful marrying of services to a building, the owner, ar- chitect, structural engineer and ser- vices engineer must collaborate in initial planning.
Hotels are a good example of the necessity for the integrated planning by the whole professional team in conjunction with the hotel administra- tion. Many miles of pipes, cables and air-conditioning ducts together with the associated plant have to be planned and accommodated. In ad- dition, a modern hotel requires steam, gas and electricity for cooking and laundering, refrigeration for cold stores, staff location devices, account- ing systems and many other specialis- ed service requirements.
Due to round the clock occupancy. further special design problems are encountered as the building must be kept fully operational while repairs and maintenance of services and plants are carried out.
Air-conditioning requirements
Of the services encountered in a modern building, it is perhaps the air-conditioning which arouses the most interest. Air-conditioning may be defined as the introduction into the
*From a paper read before the Engineer- ing Society of Hong Kong by J.N. Buss, MIHVE, MASHRAE (J. Roger Preston & Partners).
building of a required amount of clean fresh air, and that the tempera- ture and humidity of the various spaces be maintained at the desired conditions after taking into account the heat and moisture gains or losses occurring.
The arrangement and system of air- conditioning provided will be depen- dent on a number of factors including conditions to be attained, the type of building and economic considerations. Each building must be considered separately and in its entirety in or- der that the air-conditioning be effi- cient and suitable for its application.
The various items of equipment described in the following section are typical of those most commonly used in air-conditioning systems. The selection and suitability of such equip- ment is the problem of the design engineer and in a large building a combination of systems and ponents may be used to achieve the desired results,
com-
All air system: A typical arrange- ment of the all air system applied to a multi-room building is shown in Fig. 1. This has the disadvantage that
all air supplied to the various rooms is at the same temperature and is a fixed quantity. It follows that the temperature and humidity of the various spaces will vary depending on the heat gain or loss that is experi- enced.
The only practical control that can be applied to this system is to vary the temperature of the supply air. This method can achieve an average dry bulb temperature in the building but does not control the temperature in individual rooms,
This system would be better defin- ed as a cooling system and finds its best application in the conditioning of large single spaces.
Unit system
For offices, hotels etc.. the unit system of air-conditioning has found favour as separate control of each unit permits individual temperature requirements to be met. Figs 2 to 5 show various types of unit condition-
ers.
With the double duct unit, Fig. 2, the two air supplies are connected to a mixing cabinet.
Control of room
SUPPLY AIR, DUCT
FAN
HEATER
COOLER
RETURN AIR +
FILTER
PLAN
FRESH AIR
SUPPLY
AIR COR. RETURN AIR
SECTION
Fig. 1.
Far East Architect & Builder October, 1965
71