construction technology and environmental services Flashcards

Question

What is a strip foundation?

Answer 1

* Strip foundations are formed by creating a shallow continuous excavation to support the perimeter and internal walls. * They are also referred to as strip footings and are suitable for most subsoils and a light structural design.

Answer 2

* Pad foundations provide a base for reinforced concrete or steel columns. * They are usually formed by making an isolated excavation in the shape of a square or rectangle. * They often have reinforcement mesh as part of the construction and spread the load to a layer of bearing soil or rock below.

Answer 3

* They act as an earth retaining structure for the whole or part of their heights. * They are used to support and retain soils laterally so that it can be retained at different levels on the two sides.

Answer 4

* Open excavations that use battered excavation sides which are cut back to a safe angle. This eliminates the need for temporary earth work support and can be used to construct basement walls. This requires additional excavation costs and significant working space when compared to other methods. * Perimeter Trench Excavation can be used to form basement walls. This method requires earthwork support with the basement walls being constructed and then the inside of the basement is excavated. * Complete Excavation can be used in firm subsoils. The Centre of the basement is excavated first, then the basement slab cast while the sides of the excavation are supported by struts.

Answer 5

* A storey constructed below ground level.

Answer 6

* Retaining wall and raft which consists of a slab raft foundation to serve as the basement floor that distributes the building load. The basement walls serve as the retaining walls. * Box and Cellular raft which is similar to above however the internal structural walls are used to transmit and spread loads over the raft and divides the basement into cells. * Piled solution where the main superstructure loads are carried to the basement floor by columns and transmitted to the ground via pile caps and bearing piles. In this example the basement has numerous columns passing through it.

Answer 7

* Dense monolithic where the basement is designed and built to form a watertight space using high quality reinforced concrete. This requires good workmanship and strict control. Success depends on the water to cement ratio and the degree of compaction. Joints also need to be carefully designed * Tanking using materials such as asphalt, polythene sheeting, bitumen and epoxy resins. These can be applied internally or externally to provide a continuous membrane to the base slabs and walls. External application is better as it protects the structure in addition to the waterproofing. * Drained Cavity solutions can be used for new or refurbishment work. This allows a small amount of water infiltration to occur. The water is collected and then drains away to a sump or is directly discharged using a pump.

Answer 8

* Scabbling utilises piston driven carbide tipped heads which impact the surface material at a rapid rate. * This pulverises concrete or brittle coatings and can be very effective in the removal of slightly bonded coatings or where the coatings are impossible to be removed by the shot blasting process. * It can also remove level inconsistencies in concrete floors.

Answer 9

* Steel frames are often quicker to assemble in comparison to alternative methods. * They are 100% recyclable and inorganic meaning they will not warp, split, crack or creep. * They offer the highest strength to weight ratio of any building material. * Steel frames are not vulnerable to termites or any type of fungi or organism. * They are dimensionally stable and do not expand or contract with moisture or temperature changes. * Due to strict manufacturing controls, consistent material quality can be obtained due to production taking place in line with strict standards. * Steel is non-combustible so it will not contribute to the spread of a fire. * Steel frames are lighter in comparison to concrete frames and will often benefit from a cheaper foundation solution.

Answer 10

* Steel frames require fire protection to be retrospectively installed. * Fixing components may require replacement over time. * The price of steel often fluctuates and can result in a lack of cost certainty. * Installation of steel frames requires experienced builders at an additional cost. Resources can also be difficult to acquire depending on market conditions.

Answer 11

* The void or roof slab is insulated from heat loss from below and is therefore at a colder temperature than the room below during cold weather. * Insulation is located above ceiling level. * Ceiling Joists form the main horizontal members and are fixed to the wall plates. * Insulation is normally inserted between the roof joists with an air gap or void space being maintained to allow for cross ventilation. * There is a risk of condensation forming within the roof void or on the underside of the slab, so good cross-ventilation is essential. * Plywood decking is secured on to the joists and finished with the respective roof covering.

Answer 12

* Insulation is placed on top of the roof deck but beneath the waterproof membrane. * The vapour control layer is usually placed under the insulation. * This reduces the risk of condensation as the ceiling or roof void is at a similar temperature to the roof.

Answer 13

* A roof in which the insulation is placed on top of the waterproof membrane. * No vapour control is needed. * The roof void and deck are maintained at similar temperature to the room. * The insulation protects the membrane from damage but must be anchored down.

Answer 14

* The parapet wall or dwarf wall is built along the perimeter edge of the roof. * The wall height extends above roof level. * Where the wall intersects with the roof, a flashing or water proofing detail will be required along with a DPC closer placed above the flashing and at the head of the wall under the coping detail.

Answer 15

* Pitched roofs typically are made up of rafters which span from the apex of the roof and are fixed to the top of the external wall by a wall plate. * At the apex of the roof are the ridge tiles which are supported by the ridge board. * The roof covering whether slate or concrete tiles are typically fixed to roof battens. * Supporting the rafters and roof coverings are the struts, purlins and roof beams. * A soffit and eaves board may be fixed to the end of the rafters along with the guttering and rain water goods. * Vent tiles may also be used to provide natural ventilation to the roof space.

Answer 16

* Rainscreen cladding provides a screening function rather than an enclosure in its own right. * A rainscreen is used to shield a wall, whether this be of masonry, metal studwork or in some cases glass. * Usually a rainscreen is designed to permit some controlled leakage with the main functions of resistance to air and water being provided by the shielded wall behind

Answer 17

* In the stick system, the curtain wall frame (mullions) and glass or opaque panels are installed and connected together piece by piece. * Stick curtain walling systems are versatile and allow for the integration of other systems, such as sliding doors and windows. They tend to be less specialised and can be built by all types of fabricators as they are not dependent on having a large factory. * However, stick systems do require multiple steps to erect and seal the wall, which means more time is spent on site – an approximate rule of thumb would be that 70% of the work is carried out on site, with 30% in the factory. This incurs further costs due to additional labour time.

Answer 18

* Unitised systems comprise narrow-width, storey-height units of aluminum framework containing glazed and/or opaque insulated panels. The entire system is pre-assembled under factory-controlled conditions. * The unitised panels are usually craned into position, with pre-positioned brackets attached to the floor slab or the structural frame. Modern installation techniques increase the speed of erection and often minimise the requirement for scaffolding. * Unitised systems do have higher direct costs despite their reduced labour time for the install.

Answer 19

* Like unitised systems, panellised curtain walling is constructed in the factory to improve quality control and speed of erection. However, the systems comprise large prefabricated panels of bay width and storey height, which are connected back to the primary structural columns or to the floor slabs. Panels may be of precast concrete or comprise a structural steel framework and are often clad with a variety of stone, metal and masonry cladding materials. * The advantage of these systems is improved adherence to specification as a consequence of factory prefabrication, allowing improved control of quality and rapid installation with the minimum number of site sealed joints. Panellised systems are less common and more expensive than unitised construction

Answer 20

* Beams. * Columns. * Purlins. * Rafters. Eaves. * Eaves Haunch. * Base Plate. * Apex Haunch. * Cladding Rails. * Cross bracings. * Fixings.

Answer 21

* Strip foundation. * Concrete block foundation wall. * Rebar reinforcement. * Damp Proof Course. * Air bricks. * Suspended floor slab or ground floor slab. * Backfilling. * Drainage.

Answer 22

* A simple I Beam is made up: o Flange - top and bottom of the vertical steel. o Web - which is the vertical steel part of the I beam. o Root - where the flange and the web join.

Answer 23

* A durable factory applied coating on metals, such as aluminum or galvanized steel which is available in many colours. * This application is sprayed on and is followed by heat curing to give a film thickness of 50 to 100 microns. * Any holes and cutting should be carried out before the coating is applied.

Answer 24

* RHS - Rectangular Hollow Section. * SHS - Square Hollow Section.

Answer 25

* Fire Resistant paint that is sprayed on in the factory and touched up by hand on site. * It works by stopping oxygen from reaching the surface of the material it is protecting.

Answer 26

* A vertical strip or skirting, such as the weatherproofing where roofing meets an abutment wall. * It can be the roofing itself, particularly for mastic asphalt, the top part of a one-piece apron flashing, a mortar skirting or an upstand flashing, and either stepped, raking or level.

Answer 27

* This method is usually employed where stressing is to be carried out on site after casting an insitu component or where a series of pre-cast concrete units are to be joined together to form the required member. * In post-tensioning, concrete is cast around ducts or sheathing in which the tendons are to be housed. * Stressing is carried out after the concrete has cured by means of hydraulic jacks operating from one of both ends of the member.

Answer 28

* Anything that holds fresh in-situ concrete in place until it hardens, such as plywood shutters, steel pan forms, fibreglass moulds or profiled decking. * Falsework holds the formwork in place and includes items such as accessories like wedges and clips for tightening joints and to make stripping easy.

Answer 29

* A method for constructing a repetitive structure such as a core, lift shaft or stairwell. * The formwork is constantly moving upwards during the installation. * The concrete that becomes exposed must be cured enough to support the structure above.

Answer 30

* Jump forming is where a significant height of concrete is cast and left to cure. 179 * The whole formwork module is then moved up and repeated. * It works in a similar principle to slip forming but is slower and cheaper in process terms.

Answer 31

* Preventing Water Penetration o Cavity Trays are used which cross the 50mm wide cavity of a cavity wall, stepping up at least 150mm between the outer and inner leaves, to form a gutter that leads to a weephole in the outer leaf. o DPC (Damp Proof Course) – Is a strip of impervious material the same width as brickwork or blockwork wall to stop moisture rising from the ground up the external leaf of the wall. * Structurally o Lintels are used which are a small beam installed over a window or door head which carry the wall load above.

Answer 32

* Standard bricks are 215mm x 102.5mm x 65mm.

Answer 33

* The frog is an indentation in one of the bed faces of a brick, usually the top. * Bricks with two frogs are known as ‘double-frogged’, though these are less common. * Unless specifically stated, bricks should be laid frog (or larger frog) facing up, and with mortar filling the frog. * This gives a stronger wall and superior sound insulation.

Answer 34

* There are about 60 bricks per m2.

Answer 35

* Stretcher – most commonly used with walls just a half brick wide. * English – with alternating courses of headers and stretchers.

Answer 36

* Frame. * Roof. * M&E.

Answer 37

* A perforated brick to allow for ventilation into a room or an underfloor space

Answer 38

* Fire rating requirements. * Restriction for noise (Db ratings). * Visuals – Opacity vs. transparency. * Fixed or movable. * Strength requirements.

Answer 39

* Bonded Screeds which are laid on to a ready prepared rough, cleaned concrete base. * Unbonded Screeds which are laid on to a sound clean bitumen damp proof membrane. * Floating Screed which is laid with steel or fibre reinforcements on to the insulating board, which in turn can be laid on to a suitable damp proof membrane. * Resin Bonded Screed which is laid on to a clean, rough pre-prepared concrete base. The resin acts as a ready installed damp proof membrane to the top screed.

Answer 40

* A lightly rounded metal strip over the joint between the floor finishes or coverings that meet under the door leaf. * They prevent fraying and provide an aesthetic finish which also interrupt combustible flooring under fire doors.

Answer 41

* Principle Rafters to provides support to the roof covering which span from eaves to ridge. * Jack Rafters are shorter rafters that run from hip to eaves or ridge to valley. * Ridge boards which provide support and run underneath the ridge. * Wall plates receive the feet of rafters at the top of the external wall. * Hip rafters where two roof surfaces meet to form an external angle. * Valley rafter where two roof surfaces meet to form an internal angle. * Purlins are intermediate horizontal members to support the rafters. * Battens are small pieces of wood to which the roof covering is affixed. * Coverings are either laid or fixed on to a roof to protect from the elements including clay, slate or concrete roof tiles.

Answer 42

* Joists which are fixed to wall plates to act as the main support. * Furrings which are fixed to the top of joists to provide the required gradient of incline. * Particle board is fixed to top of the furrings to provide a flat surface. * Felt is applied usually made up of 3 layers and bonded with bitumen to provide a waterproof covering. * Stone chippings provide protection to the felt and also reflect sunlight.

Answer 43

* Single layer membranes o Consists of one layer of felt with a base sheet of glass fibre or polyester reinforcement impregnated with hot bitumen during manufacture. o It is then coated both sides with a weatherproof bitumen compound and dusted with sand on one layer and a thin layer of polythene on the other and left to cool. o After cooling it is cut into strips ready for use. o Single layer membranes are thin and easily punctured. o Because of this they are rarely used commercially but form the cheapest option. * Built up felt o Is constructed using three layers of felt. o The first is laid at right angles to the fall commencing at the eaves. o The next is laid parallel to the fall and the final layer at right angles. o It is then covered with stone chippings. o Built up felt is more common but can be easily punctured if proper care is not taken. * Asphalt roofing o Mastic asphalt consists of an aggregate with a bituminous binder which is cast into block ready for reheating at site. They are heated into cauldrons to a temp of 200 degrees C and are transported in liquid form to the roof. Two coats are usually required. o Asphalt roofs reduce risks of defects as it is poured on site rather than coming to site in rolls which can be damaged in transport. o Asphalt cools quickly and will need to be heated close to the roof. o Heating anything to 200 degrees C is dangerous especially in a working environment. o Asphalt roofs are hard wearing and are design to allow for transit over them. o Some companies offer a 60-year guarantee due to their durability.

Answer 44

* 3 hinges. * Intumescent strip on door or edge of frame. * A self-closing devise. * If a glazing panel is present it must be 6mm thick, wired glass to a max of 1.2m2 with 13mm x 13mm wood beads encased with non-combustible materials.

Answer 45

* The abbreviation MF commonly refers to a Mineral Fibre plasterboard suspended ceiling.

Answer 46

* This is a suspended ceiling system formed by a square grid. * These are normally quicker to construct than alternative options and allow for service runs through the void above therefore allowing greater floor to ceiling height. They also offer easy access for service repairs. * Damaged tiles can also be replaced rather than needing to repair the entire ceiling or replastering.

Answer 47

* Rolled carpets generally offer better quality and are more expensive. Rolled carpet is commonly used in dwellings. * Carpet tiles are harder wearing and are often cheaper. Individual tiles can be replaced therefore they are easier to maintain. Carpet tiles are commonly used in offices and hospitals. They are also used where raised access flooring systems adopted to allow for easier access to services that run in the void below.

Answer 48

* “Top down” is used to speed up the construction process of a building with basement levels. * The ground floor slab is cast with an access hatch. * The ground below is excavated and another slab is formed. If there is another level, the process is repeated. Piles are usually used as foundations and also act as retaining walls. It allows the building above to be constructed at the same time as the basement.

Answer 49

* “Bottom up” forms the basement and then works upwards in a traditional manner. This offers a simpler construction than top down methods of construction but will often carry a longer programme duration.

Answer 50

* A three phase supply is an AC (Alternating Current) supply that consists of three AC voltages 120 degrees out of phase with each other. * Three phase electricity is cheaper and an easier way to transmit electricity compared to single phase electricity.

Answer 51

* The incoming power supply connects to a low voltage switchboard, which in turn connects to a distribution board. * The distribution board will have an under floor busbar connected to it. The busbar has a number of sockets to which the floor box plugs into via a flexible lead. The floor box has sockets to which the appliances can plug into.

Answer 52

* Cat II Lighting are light fittings suitable for use with VDU screens. The light fittings should be designed in such a way so as to limit the amount of glare from computer screens and such like.

Answer 53

* A syphonic drainage system is an alternative to the gravity drainage system. In syphonic drainage, water is sucked from the guttering in to the drain pipe so there is no need to have pipes set at a gradient and to rely on gravity to pull the water to the drain (a vacuum is created to achieve this). * Syphonic drainage has the advantage that narrower down pipes can be used.

Answer 54

* Passenger Lifts o Passenger lifts can be specialised for the service they perform for example in hospitals with front and rear entrances. * Residential lifts o Residential lifts may be small enough for one person while some are large enough for more than a dozen. * Platform Lifts o Wheelchair or platform lifts are specialist lifts designed to move a wheelchair 2m or less they can often accommodate just one person in a wheelchair at a time with a maximum load of 340kg. * Freight Lifts o Freight lifts are similar to passenger lifts but designed to carry goods. Passengers often travel with the freight so most building regulations still apply. o Freight elevators are typically larger and capable of carrying heavier loads than a passenger elevator, generally from 2,300 to 4,500 kg. Freight Elevators may have manually operated doors, and often have rugged interior finishes to prevent damage while loading and unloading. o Although hydraulic freight elevators exist, electric elevators are more energy efficient for the work of freight lifting. * Dumbwaiter o A small freight elevator is often called a dumbwaiter, often used for the moving of small items such as dishes in a 2-story kitchen or books in a multi-story rack assembly. o Dumbwaiters are generally driven by a small electric motor with a counterweight and their capacity is limited to about 750 lb (340 kg). They may also be hand operated using a roped pulley.

Answer 55

* Maximum occupancy listings. * Fire exits with signage above that can function in a power failure. * Placing fire extinguishers and fire alarms in easily accessible places. * Restricted use of flammable materials. * Installing fire alarm control panels for quick detection and warning of fire.

Answer 56

* Automatic fire sprinklers are individually heat-activated and tied into a network of piping with water under pressure. * When the heat of a fire raises the sprinkler temperature to its operating point (usually 165ºF), a solder link will melt or a liquid-filled glass bulb will shatter to open that single sprinkler, releasing water directly over the source of the heat.

Answer 57

* Refrigeration Cycle o In the refrigeration cycle, a heat pump transfers heat from a lower temperature heat source into a higher temperature heat sink. Heat would naturally flow in the opposite direction. This is the most common type of air conditioning. A refrigerator works in much the same way, as it pumps the heat out of the interior into the room in which it stands. * Evaporative Coolers o The evaporative cooler is a device that draws outside air through a wet pad. The sensible heat of the incoming air, as measured by a dry bulb thermometer, is reduced. The total heat (sensible heat plus latent heat) of the entering air is unchanged. Some of the sensible heat of the entering air is converted to latent heat by the evaporation of water in the wet cooler pads. If the entering air is dry enough, the results can be quite comfortable. These coolers cost less and are mechanically simple to understand and maintain. * Absorptive Chillers o Some buildings use gas turbines to generate electricity. The exhausts of these are hot enough to drive an absorptive chiller that produces cold water. The cold water is then run through radiators in air ducts for hydronic cooling.

Answer 58

* VAV systems vary the airflow at a constant temperature. * These systems utilise a supply duct that distributes cooled air. * The temperature is kept constant and the air flow varies to meets the rising and falling heat gains within the thermal zone that is being cooled. * The system is made up of supply and return ductwork, a VAV box also referred to as a VAV terminal unit and air terminals.

Answer 59

* VRF systems can be made up of a heat pump system or heat recovery system which can provide simultaneous heating and cooling. * The heat pump is connected to multiple indoor units which can heat and cool independently of each other. * The energy recovered from one zone can be utilised to heat a separate zone meaning VRF systems are more efficient in comparison to other systems. * The system is made up of units a heat pump, a compressor and pipework that takes up much less space than traditional ductwork.

Answer 60

* If a suspended ceiling is not fire resistant, fire barriers will be required within the ceiling void if the walls stop at the underside of the ceiling. * The barriers will be installed between the soffit of the floor above and the suspended ceiling resulting in the ceiling void being compartmented. * It is also important to consider whether smoke stops are also required. * When services run through the barriers it is important that they are sealed to prevent fire spreading through the service gap.

Answer 61

* An uninterruptible power supply, or UPS, is a device or system that maintains a continuous supply of electric power to certain essential equipment that must not be shut down unexpectedly. * Typically, it is installed in hospitals for life critical equipment and in businesses for business-critical equipment.

Answer 62

* Generators are normally installed in buildings to act as a backup power supply should the primary power supply fail. * Generators in buildings for this reason are becoming less common as technical advances are made in UPS.

Answer 63

* Bare copper or aluminum conductors fixed inside trunking that distribute heavy-duty electrical power to tap-off units.

Answer 64

* Fan Coil Unit (FCU). * Air Handling Unit (AHU). * Variable Air Volume System (VAV).

Answer 65

* Beam Bridge with simple beam or cantilever. * Arch Bridge. * Suspension Bridge or Cable Stayed Bridge. * Moveable Bridge - Swing bridge, Draw bridge or Lift bridge.

Answer 66

* The load exerted from the bridge deck and all live loads are transferred through the wires to towers andinto ground anchorages.

Answer 67

* The towers protrude through the deck vertically to provide a connection point for the cable stays which transfer the load. * Piers support the bridge deck.

Answer 68

* The Erection or extension of a building. * Installation or extension of a service that is controlled by the regulations. * Alteration projects which will temporarily or permanently affect the building in terms of structure, fire & access. * Insertion of insulation into cavity walls. * Underpinning building foundations.

Answer 69

* A) Structure. * B) Fire Safety. * C) Site preparation and resistance to moisture. * D) Toxic substances. * E) Resistance to the passage of sound. * F) Ventilation. * G) Hygiene. * H) Drainage. * J) Heat producing appliances. * K) Protection from falling, collision and impact. * L) Conservation of fuel and power. * M) Access and facilities for disabled people. * N) Glazing – safety in relation to impact, opening and cleaning. * P) Electrical safety.

Answer 70

* They provide general guidance on performance of materials expected in order to comply with the functional requirements of the building regulations & provide practical examples. * They only provide guidance & therefore there is no obligation to adopt specific solutions if it is possible to meet requirements via a different means.

Answer 71

* Building Control Services such as the Local Authority or Approved Inspectors (Private companies set up to specifically regulate building control).

Answer 72

* Site clearance. * Enabling works. * Site setup. * Haul & access roads. * Setting out. * Excavate to reduced levels. * Excavate foundations. * Cast foundations. * Frame erection. * Cladding. * Roof. * Floors. * Services. * FF&E. * Testing. * Commissioning. * Landscaping. * Snagging.

construction technology and environmental services Flashcards

(96 cards)