By DIXON BWALYA –

IT has been stated before that in the process of designing buildings considerations taken into account include mainly three criteria requiring to be fulfilled.
The first one has to do with ensuring that the designed building will adequately fulfill the social functions which it has been designed for; meaning a room cannot be a bedroom if no bed can fit into the designed and available space.
The designed space ought to be adequately pleasant and not oppressive to live in; nor can a lounge be the same shape as a corridor because the functions for these two spaces are different.
The second requirement is to ensure that the designed building is constructed properly with good quality and suitably durable materials and workmanship so that the durability of the entire new building is guaranteed as much as is humanly possible.
The third and final consideration has to do with producing a building product that is pleasing to the eye, a psychological need in the field of aesthetics although this field does not seem to be fully developed in Zambia.
Apart from space functionality of a building there are other functions a building is expected to fulfill such as efficient discharge of storm rain water, adequate lighting levels to enable one carry out the various chores without visibility hindrances.
The building should also consider and provide for cooling and heating of rooms, ensure the space can have sufficient air changes to adequately ventilate each room, allow for means to ensure efficient cleaning of windows especially in high-rise buildings and in these days of increased pollution.
Each house hold or indeed any building type does discharge a certain amount of garbage which need to be collected and disposed off in an efficient manner and this would obviously constitute part of the design considerations to be taken into account.
However, and in view of recent developments in the construction industry one major area of concern is the trend in the area of plumbing that has been adopted which may pose potential health risks unless it is checked.
The human occupancy of buildings necessarily results in the accumulation of fluid waste and organic matter which is very susceptible to rapid decomposition and the designing of a plumbing system must ensure that these wastes are disposed off as quickly and as efficiently as possible to avoid the offensive products of decay from affecting human senses and health.
Plumbing, therefore, involves the designing and installation of pipes to efficiently carry the wastes from plumbing fixtures to the sewer, offensive gases of decomposition are generated in the plumbing pipe network or may indeed penetrate into a building’s plumbing pipes from the public sewer and hence it becomes necessary to create barriers to prevent these gases from entering plumbing pipes and ultimately and via the plumbing fixtures into the living spaces of building.
Unlike the common belief by those “graduate plumbers” moving around town with wrench spanners in their hip pockets and “taught” to use pieces of plastic bags instead of threading tape in pipe connections; the science of plumbing is based upon hydraulics and pneumatics.
The efficient sanitary and economical design of pipe arrangements and sizes can result only from a thorough knowledge of the principles involved in the theory and practical experience of the science of hydraulics and pneumatics.
While it is true that municipal regulations have been enacted in an attempt to ensure that installation of any plumbing may conform to demands of hygiene and comfort but the reality in Zambia is that there are many buildings that have ignored these plumbing regulations.
Residential flats have been constructed and occupied where cases of solid wastes being disposed off from a water closet in a flat only for the solid waste to find its way into the bath tub of the flat below.
There are a number of plumbing practices which have been in trade for a long time with improvements being regularly made as research has advanced all meant to ensure efficient disposal of the waste and thereby create health environments which minimizes occurrence of diseases.
The general approach has been based on the introduction of a combination of soil stack pipes to carry the waste, vent stack pipes to ventilate the system and carry away the offensive gases and breaks the possibilities of siphoning of water out of traps, branch vents and water traps to ensure that the offensive gases do not find their way into the living quarters nor can waste water backflow into plumbing fixtures due to sewer blockages at any point in the drainage system.
Going by the way new buildings are being constructed it looks like this traditional plumbing design approach has been abandoned.
There are mainly six plumbing fixture types in use in most buildings which include the water closets, urinals, lavatories or wash hand basins, bath tubs, shower baths and kitchen sinks; each fixture carrying waste of different chemical compositions.
It is this difference in the composition of the waste that practice in the trade advises that some of these waste materials be allowed to mix only under particular circumstances to avoid cross contamination.
For instance, a pipe supplying water to a water closet cistern is separated by an air gap such that the water pipe does not come in contact with the water in the cistern which may have germs or viruses coming from the waste pipes.
The waste from the water closet, for instance, is the most likely to carry germs and, therefore, the design should only allow mixing this type of waste with waste coming from wash hand basins, for instance, where possibilities of cross contamination are minimised.
There are cases of waste water from wash hand basins being directly discharged into urinal channels before joining a sewer line instead of passing through the gulley trap which would introduce the critical air separation; such simplified plumbing methods introduce passages of germs from the urinal back into wash hand basins used for rinsing mouths and even drinking.
There is also a very common trend where the vent stack pipes and branch vent pipes have been omitted and only the soil vent is in use and is where the waste from all plumbing fixture are connected and discharged before the sewer line on the ground level.
The result has been that once a sewer blockage occurs the combined waste would back flow into bath tubs and kitchen units, thereby introducing potential sources of diseases.
It is pure short sightedness to justify introducing such a plumbing health risk on account of economic savings.
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