This paper aims at examining domestic building services and in so doing explore options to improve their sustainability. In this paper, the focus will be on cold water and hot water services, which will represent the building services. This discussion will be in different parts, covering the following areas - cold water intake and distribution, hot water generation and distribution, electricity intake and distribution, sanitary appliances and waste/foul water disposal, and lastly, space heating generation and distribution. Water supply is a wide and relevant subject in any homestead and, therefore, the water services are essential to every person. In the past, there had been little understanding on the water services until in the recent times, when people started to develop interest in the process of water supply both cold and hot water supply. As part of the discussion, the water supply process will be examined, in addition to the above mentioned areas of discussion. This discussion on the cold and hot water services subject will be in connection to a hostel, which accommodates students of a nearby college.
Household water consumption is at a high rate with different parts of the continent, having different recordings. For instance, the United Kingdom household water consumption stands at 8,368 million litres per day, and this represents 69% of the total water consumed. Further statistics indicate that UK average water consumption stands at 150.9 liters per person a day for the un-metered households. On the other hand, for the metered households, the consumption stands at 137.0 liters per person each day. Therefore, on average, a household consumes 149.0 litres a day. Looking at the consumption in the South-East of the United Kingdom, the water consumption stands at 165 litres per person per day, which adds up to approximately 60,000 litres per person annually. Interestingly, about one third of the above water volume is responsible for flushing toilets! In the United Kingdom, water has several domestic uses, and in at least every household, there will be such consumption of water. The main uses include laundry, which covers 12% of the total water consumed, car washing and gardening uses 3% of the water, WC flushing - 33%, washing up - 9%, drinking/food preparation - 18%, and personal washing/bathing uses the largest part of the water consumed, standing at 25%. These are the general statistics as per the UK records of water consumption and its uses in most of the households in the continent.
In this paper, the discussion of cold and hot water supply will be in relation to Kailash Hostel, which is under the management of the Himalayan Children’s Foundation. It provides education and general care to under privileged children. The hostel, situated in a quiet valley, in the Gorkarna areas of Kathmandu, accommodates up to 92 children. HYF has three separate buildings, which include an administrative/dining room, girls’ dorm, and boys’ dorm. There is also a playing field for the children, where they play and do the fitness. Just like any other household, the water consumption of Kailash hostel will include the common uses of washing, drinking, WC flushing and many others. In addition to the common water uses, Kailash hostel has a swimming pool, which uses water, and it has a vegetable garden. The children have a new vegetable garden, which is on a neighboring parcel of land and this project uses much of water. The installation, construction, development, and maintenance of cold and hot water supply systems are extremely fundamental areas of concern for public health. Any building under construction will have to keep in mind this concern and ensure that the construction involves proper water supply and drainage. Currently, the supply of water to the Kailash hostels is through a bore-well 300 feet, but it is not palatable. For this reason, a project, which aims at supplying the hostel with pure drinking water, will be useful to the villagers around.
How the supply of water in the Kailash hostel will be useful to the villagers around? The project, which aims at supplying water to the hostel, has the following structure. It will have a collection tank at the hostel with a 1.5 km pipeline, which runs through the village to the hostel. This construction will have to base on the appropriate water supply constructions, which will be described in the following discussion. The water cycle should be a paramount concern to anyone, constructing water supply to a building. The cycle is a common thing, starting with collection, treatment, distribution, use, and then disposal. The first step is to collect water, which can be in a dam, tanks or in any place, where water can be stored. People collect water from different sources like oceans, lakes, rivers, rain, and streams. The process of water collection will involve placing pipes in the water sources and, then, directing the water pipes to a storage facility. After the water collection, goes the next step of treating the water. Treating water ensures that the consumed water is safe for the users and poses no danger to their health. Treatment can be done at the collection point before distribution, which is the next step for the water cycle. Distribution is usually done through water pipes to the consumers’ households. After the use, there is water collection again, which is, then, treated and disposed. Disposal is usually made in the water sources like oceans, where the water is collected again and the cycle goes repeatedly.
Underground water supplies vary in terms of depth, for instance, there is a shallow well, where the water is just above the impermeable layer of the ground. A deep well goes way in the ground level in to the permeable layer, which comprises of gravel. Another underground water supply is spring water, which is almost like a shallow well, but, in its case, a user does not have to dig for the water to come up. Currently, the Kailash hostel is making use of the underground water supply by having a 300 feet borehole. This can fall in the category of a deep well. Water collection will require electricity or some other form of energy to pump the water to the various water collection points. Water collection can be from extremely far sources, and this will call for a complex pipe network to ensure the water reaches the users or the collection point before the other steps can be followed. Now, a focus is on the cold water treatment.
Water treatment scheme is a process, which depends on whether the water is at a collection point, or it is still at its source. Once people have water in the collection reservoirs the first step is to carry out the primary filtration. At this point, the water treatment aims at removing any micro-particles from the water. The water goes to the next stage of secondary filtration, which makes use of slow sand filters. At this stage, the water is pure and does not contain any impurities like sand particles. Chlorination is the next step, which ensures the water is safe from other unseen impurities and adds nutrients to the water. This is in a contact tank and it makes use of some chemicals, which contain chlorine. Once this step is done, the pumping of water to the various users can be done. This is a complex process, and it is not the obligation of each household to carry out the water treatment. Each household can have its own treatment, once the water gets to their homes or taps, but the main treatment is at the water collection point. The complexity the system has will mean the water supply task is under the supervision of water authorities in that area. The water authority is in charge of ensuring that the water is of appropriate quality. Suitable quality of water comprises of the following: potable, clarity, taste, bacteria, additives, and odorless. All these make up the elements of quality and consumable water. The water authority equally has the mandate to ensure sufficient quantity of water. For the water to be of sufficient quantity, it needs to have adequate and consistent pressure and a large volume of supply. Water problems arise, when there is no sufficient water supply, and when the authorities supply inappropriate water.
As long as the water supply services to most households are in the capacity of water authorities, its mandates only go to a certain extent. The water authority is in charge for the supply of water to the limit of the property through its pipe work, up to and including the stopcock. From this point, the owner of the premises takes care of the system. It is necessary that the underground pipe work should be a minimum depth of 750 m to lessen the risk of freezing and other damage. The water authority will have the obligation of putting up meters, which will enable users to control and maintain their water consumption. There are external and internal meters, which monitor the water consumption. The constructions of how cold water services enter a house vary, depending on the position of the building. An example is the pipes, entering solid floor and the suspended floor. Different water temperatures will call for different designs, which help in the water supply. In the next section, the focus is on the cold water systems.
In the case of cold water services, there are two systems types, which are the direct system and indirect system. The direct system operates in such a way that all appliances take the water directly from the incoming main supply, including the cold storage reservoir. This means that any appliance, which requires cold water, gets it directly from the main supply, which may be tank or reservoirs and not the storage appliances. The hot water cylinders, WC, basin, etc. are just examples of the appliances, which will have the water from the main supply. The main supply can be on the roof of the building, or on the side, or on the solid ground, and it will have a connection of pipes from the main pipe, supplying water to the appliances. On the other hand, using the indirect system, the appliances do not get their water supply directly from the main water supply. The appliances get their water supply from the cold storage cisterns, which normally are the toilets, bath, basins, hot water cylinder etc. Indirect systems have several merits, making it the most common system in most households. Indirect systems will have a water reserve that should be sufficient for 24 hours of use, it will not contaminate the main supply of water, and there will be fewer chances of water noise. In addition, the water pressure is the same at mixer taps and leakage tends to be less at lower pressures in case of a fault. The main disadvantages of the indirect systems are the following: it will call for a lot of space and structural support for the water storage cistern, it is expensive - the initial capital and maintenance of the system, and there is a risk of frost damage to water storage cisterns.
The construction of water storage cisterns will depend on the household size and consumption of water. Storage requirements for tanks are just about 24hours supply of water for the dwellers of the building. This requirement varies, depending on the use, to which the building is put. For example, a domestic dwelling should permit more water per person than a school. The recommended proportion of domestic storage can be apportioned 67% cold and 33% hot. In this paper, the focus is on hostel, which has a large number of people consuming water and, therefore, the most appropriate consumption is 90 litres per person.
In the case of hot water supply, the constructions for the systems differ from the cold water services. The main notable difference in the two services is the use of energy in the hot water service, which is not in use in the cold water services. For this reason, the system design for the hot water system will vary, and it will include the following main areas - temperatures, water pressure, quantity of water, quality of water, cost, energy efficiency, fuel and emissions, and maintenance. The recommended hot water temperatures in hard water areas are not above 65 degrees to circumvent precipitation of lime scale. In soft water areas, the temperatures can be at 70 degrees. These ideal temperatures are necessary to kill the bacterium, which causes the legionnaires disease. This bacterium can survive in temperatures of 37 degrees, which provides an ideal environment for the multiplication of the bacteria.
In order for Kailash hostels to have hot water services, the constructors will have to decide on the ideal temperatures of the water. The water temperatures will depend on several factors like the legionnaires disease, the application of water, energy efficiency, safety, water hardness, pipe, pump, and water storage equipment. Since the main users of water in Kailash hostel will be children, the temperatures can be slightly above 60 degrees, which will be safe for children. The local systems will be the most advisable in the Kailash buildings, which will supply hot water services. This means that, in the water storage category, the buildings will be installed with local self-contained systems. This will include non- storage units, storage units, gas or electric. These systems will have different water types, which are the pressure type, cistern type, and free outlet type.
In this section, the paper looks at the centralized systems of hot water services. Under this category, there are direct and indirect systems. Both types will have primary and secondary circuit, which will be either vented or unvented. The components of the centralized systems will be wall hung gas boilers, condensing boiler, and a balanced flue. In addition, there will be floor standing boilers, biomass boiler, and calorifier. Putting up hot water systems can be complex work because the constructor will have to keep in line with some regulations, put by the water authorities. In most cases, the hot water constructions will be in line with the users’ demands and applications of water and, therefore, this is not the duty of the water authorities. According to the building regulations, 2006 part L, it has an emphasis on the conservation of power and fuel. The conservation of power and fuels in buildings will be by limiting the heat gains and losses. This will be via thermal elements and other areas of the building, from pipes, vessels, and ducts, which are useful in space heating, cooling and hot water services. Another regulation way is through the provision and commission of efficient fixed building services with valuable controls. Providing users with sufficient information, concerning the building, maintenance requirements and the fixed building services will also be necessary in regulating the power and fuel in the case of hot water services.
In any installation of hot water services in a building, there have to be safety measures, taken for the unvented water circuits. The flow of temperatures needs to be in the range between 60 and 65 degrees with 95 degrees being the limiting temperature for thermostat control of the boiler. The central and local hot water systems have some notable differences, which are: centralized systems provide large bulk storage and require less maintenance, cheaper fuel maybe used, and there is heat loss in pipe work. As for local units, there is a greater risk of fire; there is no need to pump water, lots of gas or electric connections, and saving in space. The energy use of hot water can be calculated, using the following formula – water, used by space heat capacity by the temperature difference, plus system loss, divided by boiler efficiency. The energy saving measures in hot water services include reducing the length of dead legs, water flow temperatures, distribution heat loss, and control time of use. In conclusion, any person who needs to acquire water services, whether cold or hot, needs to be aware of all the above information, so that they can have an efficient and reliable water supply. Both systems can be available in a building, depending on the users’ needs and application.