Construction Technology Flashcards
(163 cards)
1
Q
what is topographical survey
A
A topographical or a land survey is an accurate representation of the area of interest showing all natural and man-made feature with levels. Shown as three dimensional points all features including the property, land features and physical boundary details are presented on a scaled survey drawing.
2
Q
what is substructure
A
All structure below the superstructure, i.e.
all structure below the ground including the ground floor bed
3
Q
what is superstructure
A
all internal and external structure above the substructure
4
Q
what is meant by primary superstructure
A
external walls, stairs, structural walls, roofs
5
Q
what is meant by secondary superstructure
A
Raised floors, suspended ceilings, balustrades, doors
6
Q
what is meant by internal finishes
A
paint, tiles, carpet, stair nosing
7
Q
what is the external envelope of a building
A
The materials and components that form the external shell or enclosure of a building.
May be structural or non structural
8
Q
what are the building regulations
A
Statutory instruments that set out the minimum performance standards for the design and construction on buildings.
Supported by approved documents A-R and regulation 7
9
Q
Name the approved documents
A
A-Structure
B-Fire safety
C-site preparation and resistance to contaminants and moisture
D-Toxic substances
E-Resistance to the passage of sound
F-Ventilation
G-Sanitation, hot water safety and water efficiency
H-Drainage and waste disposal
I-
J-Combustion application and fuel storage systems
K-Protection from falling, collision and impact
L-Conservation of fuel and power
M-Access to and use of building
N-Glazing safety (withdrawn)
O-
P-Electrical safety
Q-Security
R-Physical infrastructure for high speed electronic communication networks
Regulation 7-Materials and workmanship
10
Q
what are British Standards
A
- Publications issued by British Standard Institution
- Give recommended minimum standards for materials, components, design and construction practices
11
Q
what are International Standards
A
- Prepared by International Organisation of Standardization
- Compliment BS
12
Q
what are the typical components of site investigation
A
Objective-to collect and record data to help in design and construction
Should include info of adjacent sites that impact:
-boundary hedges/fencing
-existing trees
-existing buildings
-ground water conditions
-soil investigation (trial pits)
13
Q
what are soil investigation
A
Objective:
- determine suitability of site for proposed works adequate and economic foundation design
- identify potential issues
14
Q
what are main site considerations for a contractor setting up on site
A
- access considerations, approach roads, etc
- storage considerations
- accommodations
- temporary services
- plant
- fencing/hoarding
- health and safety
15
Q
what is retained facade
A
facade of the building is retained whilst everything behind the front wall is demolished
16
Q
why are facades retained
A
- often listed
- aesthetics
17
Q
what consideration would you make if you were to retain a facade
A
- temporary support structure
- cleaning/restoration requirements of facade
18
Q
what are temporary works
A
- may not appear on construction drawings
- methods that are required to ensure safety construction, e.g. propping. These will be removed once permanent supports are in place
19
Q
what is landfill tax
A
- brought in by government in 1996
- to reduce landfill waste and promote recycling/reuse, promote research into waste practices
- applies to all waste disposed of at licensed landfill sites unless specially exempt
- administered by HM customs and excise
20
Q
what are the landfill tax rates
A
£94.15/tonne for active waste
£3/tonne for inactive waste
21
Q
what is active waste
A
- substances that either decay or contaminate land-which includes household waste
- expensive to dispose of
22
Q
what is inactive waste
A
- biologically or chemically inactive, don’t give out harmful residue
- do cause problems with filling up areas
- cheap to dispose of
23
Q
what is a tower crane
A
- a tower crane is a tall crane used for lifting objects into high places
- the arm allows a longer reach with 360 degree access
- a longer boom reduces the payload capability
24
Q
how would you erect a tower crane
A
using a smaller crane
25
what issues might cause a tower crane to suspend its use
adverse weather conditions, particularly high winds
26
what is scaffold
- temporary working platform erected around the perimeter of a building or structure to provide a safe working place at a convenient height
- usually required for working above 1.5m high
27
what is shoring
- form of support given to existing building
| - precaution against damage or injury caused by collapse of structure
28
what are hoists
designed for the vertical transportation of materials or people
29
what are foundations
Foundations provide support for structures, transferring their load to layers of rock and soil that have sufficient bearing capacity
30
what is a dead load
- permanent and static loads
| - predominately the structure itself
31
what are live/imposed loads
- usually temporary
- changeable and dynamic
- occupants, furniture, equipment, vehicles
32
what are wind loads
- the movement of air against the structure
| - particularly important on tall buildings and building with a light-weight dead load
33
what are the main components of concrete
water, aggregate (rocks, sand etc), cement
34
what is aggregate
natural stone, crushed rock, gravel
35
what is borehole
- a borehole can be used for soil investigation of geothermal heating solutions
- boreholes are the most effective solution for soil investigations where the foundations are to be over 3m deep
36
what are piles
a series of columns constructed or inserted into the ground to transfer the load of a structure into the soil
37
what are different types of piling
- replacement/bored piles (reinforced concrete situ)
- displacement/driven piles (pre-cast-steel, composite)
- basement walls (secant piles. sheet piles)
38
what are sheet piles
- sections of sheet materials with interlocking edges that are driven into the ground to provide earth retention or excavation support
- typically made of steel
- often used for retaining walls and underground structures
39
what are secant piles
- intersecting steel reinforced concrete piles
- primary female piles are installed first, with secondary male piles installed in between them. Overlap of roughly 3 inches creating a flush finish
- useful in top-down construction temporary waterproofing
40
what are bored piles
- auger is used to excavate soil, then concrete is poured in
- variation of this is where a continuous flight auger is used to bore piles and fill core with bentonite slurry. Concrete then poured into core, displacing the bentonite slurry. due to it's denser makeup.rarely used now due to environmental impacts or bentonite
- minimal vibration
41
what are pre-cast piles
- pile brought to site and hammered into the ground
- high noise levels associated with installation
- lack of flexibility in terms of depth required
42
what are different ways that piles transfer their load into surrounding ground
- end bearing piles: pass through soft strata to firm strata. load transferred through toe of pile
- friction piles: through sheer stress against side of piles
- tension piles: through the length of pile to reduce overturning moments on the building caused by uplift forces
- laterally loaded piles:horizontal forces in situations such as bridge piers. similar to above
43
when would you use bored piles
- in cohesive subsoils for the formation of friction piles
| - when close to existing building due to noise/vibration limitation
44
when would you use pre-cast concrete piles
- wen there is soft soil deposits lying on the firmer strata
| - when noise/vibration isn't a concern
45
what are the risks for PQS regarding cost control with piling
- End depth of piles are never a certainty, procurement route determines who takes the risk
- Traditional/D&B=contractor
- Management Contracts=Employer
46
what is a raft foundation
- used to spread the load of superstructure over a large base and reduce load//m2 area
- generally reinforced concrete slabs
47
when would you use raft foundations
- in low bearing capacity soils
- where settlement is likely
- where small areas are small and structural load low
48
what is strip foundation
shallow foundations used to provide a continuous, level strip to support a linear structure such as a wall
49
when would you sue a strip foundations
- most sub soils
| - light structural design
50
what are pad foundations
a forms of spread foundation formed by often square pads that support single-point structural loads such as columns
51
what are retaining walls
they act as an earth retaining structure for the whole or part of their height
52
what consideration should a contractor make when building a retaining wall
pressure of water/earth acting on wall
53
what are the main types of excavation
- Open
- Perimeter trench excavation
- Complete excavation
54
what is open excavation
- use battered excavation technique which is excavating the soil with the sides left at a safe angle so as to not collapse
- save money on temporary works
- extra excavation costs due to extra soil being moved to ensure sides are at a safe angle
- requires free space on site for angled side. wouldn't work on site boundary
55
what is perimeter trench excavation
Trenches are dug with required support around basement perimeter. Basement walls are formed, then inside of basement is excavated.
56
what is complete excavation
- center of basement is excavated
- basement slab is cased while sides of excavation are supported by struts
- basement walls formed
- used when sub soils are firm
57
what is a basement
A storey below ground floor
58
What are three main types of basement construction
- retaining wall and raft (monolithic)-slab raft foundation distributes building load-basement walls are retaining
- box and cellular-similar to above but internal structural walls transfer and spread loads over raft, dividing basement into cells
- piled-superstructure load carried to basement floor by columns and transferred into ground via pile caps
59
what are three main methods of waterproofing a basement
- dense monolithic-basement designed to form watertight space
- tanking-asphalt or similar resin applied internally or externally to provide continuous membrane to base slab and walls. External better as it protects substructure.
- drainage cavity-accepts small about of water seepage, collects and drains this away. Inner non-load bearing wall forms cavity wall for water to drain into, can be used on refurb work
60
what is scabbling
- It's a process of reducing stone or concrete
| - removes thin layer from surface of concrete
61
why is scabbling used
- roughen surface of concrete for better grip
- prepare surface for painting/sealing/coating
- reduce levels/level surface
- decoration
62
what are the technical advantages of steel frame construction
- quick to assemble
- recyclable materials
- high strength to weight ratio
- not vulnerable to termites, fugi, etc
- consistent materials quality as produced in strict accordance with national standards
- non-combustible so won't contribute to spread of fire
- lighter than concrete
63
what are the technical advantages of steel frame construction
- needs fire protection/corrosion protection
- parts may need replacing
- price is variable, could be high market dependent
- requires experienced builders
- will fail (collapse) before wood in a fire in spite of not being combustible
64
what are the technical advantages of concrete frames
- could be cheaper than steel dependant on market price of steel
- doesn't require additional fire protection
- slower construction will help cashlow
- low maintenance with in situ concrete frames
- cladding can be fixed to it and replaced easily
- good sound and heat insulation
- in situ allows alteration at later stages
- can deal with complex geometry better than steel work
65
what are the parts of I Beam
- Flange (top and bottom of the 'I')
- Web (the vertical steel, runs between the two flanges. Long part of the 'I')
- Root (where the flange and web meet)
66
what is a steel table
- table that provides standard information on steel sections
| - different table for different beam/columns
67
what is the weight of steel
7850kg/m3
68
what is powder costing
- a durable factory applied organic coating on metals available in many colors
- Polyster, acrylic, epoxy spray followed by heat curing
- any holes made/cuttings should be done prior to application of coating
69
what are the advantages of powder coating
- stops corrosion
- stops abrasive damage
- stops metal reacting with other chemical
70
what is RHS
Rectangular Hollow Section
71
whats is SHS
Square Hollow Section
72
what are UBs and UCs
Universal Beams & Universal Columns
73
what is intumescent paint
fire resistant paint
74
what are connections (steel) and what percentage would you expect them to be
- plates, bolts or welding
| - 5%-10% by weight
75
what is power floated and why
- Power float is a hand-operated machine
| - It's used to produce smooth, dense level surface finish to insitu concrete slabs
76
what is post tensioned concrete
- Post tensioning is a technique to reinforce concrete formed insitu
- can be used to join a series of precast units
- the concrete is cast around ducts or sheathing in which the tendons are hosued
- steel tendons are pulled tight once concrete is cured using hydraulic jacks from one or both ends
- the stretched steel tendons are then capped
- essentially, the steel tendons are pulling the concrete slabs together by trying to contract.
77
what is formwork
- Anything that holds in-situ concrete in place until it hardens
- can be plywood shuttering, steel pan forms
- can be supported by props, centering (formwork for floors/slabs) or falsework
78
what is slip forming
- a method for construction repetitive structures such as core, lift shaft or stairwell
- slip forming is a method of construction in which concrete is poured into the top of a continuously moving formwork. As the concrete is poured, the concrete is poured vertically at a speed which allows the concrete to harden before it is free from the work at the bottom.
- formwork constantly moves upwards at approx. 1inch every 10 mins
79
what is jump forming
- a significant height of concrete is cast and left to cure
- the whole formwork is then moved up and action is repeated
- cheaper than slip forming but slower
80
what is A182 mesh
- mesh used to reinforced concrete slabs
| - metal lattice
81
what is a cavity tray
A damp proof course that crosses the 50mm wide cavity of the 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
82
what is a damp proof course
a strip of impervious material the same width as brickwork or block work wall to stop moisture rising from the ground up the external leaf of the wall
83
in a brick/block wall, how are window openings dealt with structurally
through use of a lintel-a small beam over the window or door head to carry the wall load
84
what is the size of a brick
standard size 215mm*102.5mm*65mm
85
what is the brick frog and which side does it go on?
- the frog is an indentation in one of bed faces of a brick, usually the top
- bricks with two frogs are known as 'double frogged' through these are less common
- bricks should be laid frog (or larger frog) facing up, with the mortar filling the frog
- creates a stronger wall and superior sound insulation
86
what are the different types of brick bond
Flemish Bond-the bond has one stretcher between headers, with headers centered over the stretchers below
Stretcher bond-most common, walls just half a brick wide, Stretcher face slide showing
87
what are the different faces of a brick called
Stretcher=long side of brick face
Header=short side of brick face
Sailor=when bricks are stood up vertically, the wide face is called the sailor
Soldier=when bricks are stood up vertically, the thinner face is called the soldier
Rowlock Stretcher/Shiner=when the brick is sitting on it's stretcher, the wide face that was previously the top called the shiner
Rowlock=In the above situation, what was previously the head is called the rowlock
88
what is a rain screen cladding system
- non-structural external surface
- protects everything inside from external weather
- formed of outer protective skin (metal, timber,glass, composite panels), supporting frame, a cavity and water-resistant internal materials which includes a layer of insulation
- three basic types are drained and ventilated, vented, and pressure equalized rain screen systems
89
how are cladding panels fixed to a steel frame.
- bolted (useful when may require being undone and cheaper than welding)
- riveted (fastest, like a nail)
- welded (melted together, maximum strength)
90
what other elements will be affected by type of cladding used
- M&E
- Roof
- Frame
91
what is an air brick
- a perforated brick to allow ventilation into a room or under a floor space
- not a weep hole
92
what factors may affect choice for internal partitions
- fire rating requirements
- noise requirements (Db rating)
- visual requirements (glazing)
- Flexibility required (movable/fixed)
- Strength (to hand thing from walls etc)
93
what is a rebate
a cut into a material to house another material e.g. glass.
94
how do you construct a glazed partition
- Glass is fixed into a frame, steel or wood
- Glass placed into a rebate, rebate is filled with putty/beading to hold it in place
- This frame is then placed within walls/columns where required, usually held in with putty.
95
what is bonded screed
laid onto a ready prepared rough, cleaned concrete base
96
what is unbonded screed
laid onto a sound, clean Bitumen damp proof membrane
97
what is floating screed
screed laid on acoustic or thermal insulation. This is a type of unbonded screed
98
what is the purpose of a threshold strip
- a metal strip between the floor finishes or coverings that meet under the door leaf
- prevents fraying, creates a more fluid look and interrupts the spread of fire for combustible floors
99
what is a hip rafter
the rafter extending from the wall plate to the ridge and forming the angle of a hip roof
100
what is a ridge in terms of roof construction
Apex beam in a roof
A ridge is the horizontal junction between two roof slopes (duo ridge), or a roof slope and a vertical wall below a roof slope, (mono ridge). It's the highest point of any roof slope, making it more exposed than most other parts of a roof. A ridge is one of the last parts of the roof to be completed
101
what are jack rafters
the rafters that runs from the hip to the eaves
102
what are principles/common rafters
Run from the ridge to the eaves.
| Main structure of the roof
103
what are wall plates
Receive the feet of the rafters at the top of external wall
104
what are purlins
Horizontal beams that are used for structural support
105
what are batterns
Small length of wood that run between rafters horizontally. To these , the roof cover is fixed.
106
what types of roof covering may you find on a pitched roof
- slates
- pan tiles
- Zinc
- Copper
- Thatched
107
what are elements of a flat roof?
Joists-fixed to wall plates to act as main support
Firings-fixed to the top of joists to required incline
Particle Board (ship board)-fixed to top firrings to give flat surface
Felt-3 layers bonded with bitumen to give waterproof covering
Stone chipping-to give protection to felt and the reflect sunlight
108
what is a single layer membrane
- one layer of felt consisting of a base sheet of glass fibre or polyester reinforcement, impregnated with hot bitumen during manufacture
- coated both sides with weatherproof bitumen compound
- easily punctured and rarely used
- cheapest option
109
what is built up felt
- constructed using three layers of a single layer membrane
- first is laid at right angle to the fall, second laid parallel to fall, third at right angle
- covered with stone shipping
- easily punctured if care not taken
- more common than single
110
what is asphalt roofing
- aggregate with bituminous binder which is cast into block ready for reheating at site
- headed into cauldrons to 200 degrees celsius
- transported in liquid form to roof
- two coats usually required
- reduce risks of defects as no risk of damage ne route to site
- cools quickly, must be heated close to roof
- hard wearing and designed to allow transit. some companies offer 60-year guarantee.
111
a door requires a 30min fire rating. What features would you expect that door to have
- 3 hinges
- intumescent strip around door or frame
- self closing devise
- 6mm thick glass
112
what is MF ceiling
Mineral Fibre plasterboard suspended ceiling, typically used in office spaces
113
what is metal grid ceiling and what are the benefits
- suspended ceiling system formed by square grid
- quick construction
- allow services to run through the voids allowing greater floor to ceiling height
- easy access to services
- damaged tiles can be replaced
114
what are the benefits/disadvantages of rolled carpets
- rolled carpets generally better quality
- more expensive
- used in dwellings
115
what are the benefits/disadvantages of carpet tiles
- hard wearing
- lower quality
- individual tiles can be replaced therefore easy to maintain
- used on offers
- easy access to flooring, useful when raised flooring is used
116
what is top down construction
- used to speed up construction for building with basement levels
- Ground floor slab cased with access hatch
- ground below excavated and another slab is formed
- Piles used as foundations and act as retaining walls
- structs/propping required for retaining walls
- this allows building above to be constructed at the same time as basement
117
what is bottom up construction
- forms the basement then works upwards in a traditional manner
- simpler but longer programme
118
How is power distributed to floor boxes in raised floor
- power supply connects to low voltage switchboard which in turn connects to a distribution board
- the distribution board will have 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 which appliances can plug into
119
what is a switchboard
a devise that directs electricity from one source to supply several smaller currents for further distribution
120
what is a distribution board
A device that divides electrical power feed into subsidiary circuits while providing a protective fuse or circuit breaker for each circuit in a common enclosure
121
what is a three phase electrical supply
- An AC supply that consists of three AC voltages
- Enables a stronger consistent source of power
- used for lifts, big buildings
- small electrical objects and houses do not need three phase electrical supply. Single phase electrical supply fluctuates 60 times/second, so we do not see bulbs flicker etc.
122
what is an AHU
- Air Handling Unit
| - Used to regulate and circulate air as part of a HVAC unit
123
what is an FCU and how does it work
- Fan Coil Unit
- Condition the local air to suite the temperature requirements of the immediate space
- Main AHU will feed fresh air through main duct. Branches will flow off main duct into different rooms
- Air will blow from duct into FCU (not directly connected, gap between duct and FCU allows for recycles air from grille in ceiling to be sucked into FCU also)
- Air inside FCU gets sucked through fans, through heating or cooling coils, then out the other side
124
how do heating coils work in FCUs
there are many plates in FCU which pipes of hot water run through. This heats up the coils/plates/pipes. This heat is transferred to the air passing through
Could be electric rather than water
125
how do cooling coils in FCUs work
cold water from the chiller is fed through the cooling coil. The air transfers energy to the cooling coil, cooling itself down before flowing into the space
-As the air cools, it condenses. The condensation will run into a drip tray at the bottom of the FCU and a pipe will take it away
could be a refrigeration unit instead of chilled water
126
does every FCU need to have fresh air supply
No, but each room must have at least one supply of fresh air.
Regulations state a certain amount of fresh air is required, see Building Regs App F for detail for different building types.
127
what are chilled beams
- supply air is usually 100% ventilation air
- air pumped into supply inlet and out of nozzles either side of chilled beam
- this creates a low pressure zone that draws air into the face of the chilled beam
- this air goes through chilled beam and flows back out through the nozzle with more ventilated air.
128
what are the benefits of chilled beams vs FCUs
chilled beams:
-lower carbon emissions when first released, however not necessarily anymore due to advancement in FCU technology
-FCUs:
cheaper than chilled beams; more flexible and can eat and cool air
129
what are the benefits/disadvantages of a steel frame building vs a concrete frame building
CONCRETE:
-waste materials can be included with/in mix, e.g pulverized fuel ash
-short lead time
-slower erect on site, through precast and improving methods are speeding this up
-fire protection is inherent
-most cost effective depends on the market. Steel fluctuates
-Requires steel reinforcement. Good compression strength but requires reinforcement for tensile strength
-can be moulded into different shapes but will struggle with open spans and/or high floor -floor height
-will not corrode. steel reinforcement must be sealed/protected
Steel:
-long lead time
-fast erect on site
-needs fire protection, prefab steel can allow for thin application off-site though
-lighter, as much as 60% lighter than concrete. Allows for less substantial foundations
-less labour required to install
-strong, concrete lacks tensile strength
-more flexible, good for long open spans due to strength
-requires protection from corrosion
130
what is cladding
components that are attached to the primary structure of a building to form a non structural, external surface
131
what are common types of cladding
- curtain walling
- rain screen cladding
- GRC panels
- Precast concrete cladding
132
what are common types of cladding
- Curtain walling
- rain screen cladding
- GRC panels (glass reinforced concrete)
- Precast concrete cladding
133
what is curtain walling
- Glazed or opaque infill panels fixed to a lightweight frame
- vision panels, spandrel panels, aluminium panel, louves/vents
- Fixed using stick or unitised system
- lightweight, maximize daylight, can provide good thermal performance (opaque panels)
- Installation costs/maintenance costs can be high
134
what are the two methods of fixing curtain walling to a primary structure
- stick system or unitised system
- stick system is where stick like frames are installed between beams, then panels fixed to them
- slow to install and require sealant around perimeter. Quality depends on skills of installers
- unitized systems are all-in-one panels that fix together between beams
- fast to install but long lead time due to prefabrication process. Costs a lot to ship and store.
135
what is precast concrete cladding
- concrete panels are formed off-site
- off-site manufacturing means it can be moulded into different shapes, colours, in controlled conditions to less wastage
- transported to site, tower/mobile cranes lift them to position
- Panels can be fixed to frame or can be supporting itself
136
what is GRC
- Glass Reinforced Concrete
- Glass Fibres imbedded in concrete matrix
- Appears similar to natural stone
- can take any form
- 80% lighter than steel reinforced concrete, therefore reduced installation costs
- BREEAM rating
- Fragile in transport
- labour intensive to manufacture and can be expensive if bespoke (no economies of scale)
137
what are the advantages and disadvantages of masonry facades
-masonry facades are generally load bearing facades made from brick/stone/block
Benefits:
-inexpensive to repair
-good to fire resistance
-good thermal mass and high acoustic performance
138
what is prefabricated construction
Prefabrication is the practice of assembling components of a structure in a factory or other manufacturing site, and transporting complete assemblies or sub-assemblies to the construction site where the structure is to be located
139
what is the minimum height for a balustrade
See Building Regulation K
-In schools:
flights of stairs-0.9m from datum (standing level)
landings-1.1m from datum
140
name some features you may find on a historic facade
- cupolas
- Gargoyles
- Chimney Stacks
- cornices
- terrocotta
- Portland stone
141
what is a yard gully
- drain in the ground for rainwater to fall into
- maximum paved area per gully should be 400 m2
- fall should be 1:60
142
what is drainage channel
- long channel for rainwater to fall into
- fall should be 1:20
- where the fall is all one way, away from a building
143
which building regulation document covers drainage
Approved document H
144
what is a soil stack
A pipe that takes waste water from toilets, urinals etc away from building.
Ventilated
145
what is a waste pipe
Pipe that wastes waste water from sinks, showers, baths, etc.
146
what is an attenuation tank
- Avoids flooding during heavy rain
- Overflow of water in underground drainage overflows into perforated pipe
- water falls through holes into attenuation tank, where it is stored and slowly released
147
which building regulation document related to fire safety
Approved document B
148
what are methods of fire safety
- Intumescent paint
- Intumescent strip on doors
- Sprinklers
- Fire doors that shut
- fire stopping voids between rooms to stop the spread of fire
- fire alarms
149
what height must a building be for sprinklers to be compulsory
30m
150
what is an open loop system
- relates to the electrical control system
- external conditions do not affect systems output, e.g. temperature will not affect whether AC comes on/off. It may be simply a timer
- Good because simple, easy to construct and stable
151
what is an closed loop system
- Relates to electrical control of systems
- external condition affect system output, e.g. if the building gets too hot the AC will turn on
- Good because they are intelligent and more useful, downside is they are more complex /difficult to install/expensive.
152
what are the components that make up access control
- Access Controller (decides whether people are allowed in or not)
- reader (card, key pad)
- door contact (between door and frame, allows door to know whether it's open or closed)
- door strike/magnetic lock
- REX (request to exit) allows you leave without any card
153
what's the difference between end bearing piles and friction piles
End bearing=load transferred to rock/gravel largely at base of pile
Friction=load transferred to ground largely through the sides of the pile (shear force)
154
what is a vented rainscreen cladding system
- Cavity open at bottom
- Provides drainage but no ventilation
- warm cavity, no ventilation (should be called drained really)
- warm cavity provide dew point close to outside
- shouldn't e used above 4 storeies due to higher load +higher risk of water penetration
155
what is drained and vented rainscreen cladding system
- not watertight
- cavity must be open at top and bottom
- cavity must provide drainage and promote ventilation
- protect cavity with overhang
- provide backing structure with moisture barrier
- non-hygroscopic or closed cell insulation
- excessive high D+V systems should be avoided
156
what is a pressure equalized rainscreen system
- Cavities are compartmentalized
- Openings calculated to allow rapid ingress and egress of air resulting in very low wind load on panel themselves
- water ingress reduced by 'equalisation' of internal and external pressures
- drained above compartment levels
- suited to tall areas of rainscreen, typically used over 4 years
- design intensive
- compartmentalization stops spread of fire
157
what are the different grades of waterprrofing
- some seepage.damp is tolerable. Car Parks, etc
- No seepage is acceptable. Some damp is tolerable depending on use. Workshops, boiler rooms etc.
- No seepage or damp is tolerable. Offices, homes etc.
158
what is type A water proofing
BS defines as 'barrier protection'
material e.g. waterproof concrete applied to walls
-called'basement tanking' when applied to cellars/basement
-perfect for grade 1 waterproofing
159
what is type B water proofing
BS defines as the structure itself being a waterproof shell
- a build of reinforced concrete supplemented with a method of controlling water ingress at construction joints (such as hydrophilic waterbar)
- typically achieve grade 2 waterproofing, but that's not the limit of its application.
160
what is type C water proofing
- BS defines where a structure itself provides initial resistance against water, but also incorporates a drained cavity to collect ground water ingress and direct it toward drain/pump for removal
- ideal for grade 3 waterproofing.
161
what is the heat gain
the term given to a temperature rise within a space due to heat from surfaces, heat originating from other sources within the space (such as heating appliances, ovens, people, mechanical systems, lights and computers)
162
what weather conditions can affect the way concrete sets
- below 5 degrees takes longer to set
- rain water into mix=bad
- frost=bad
163
what is grey and brown water
Grey water=water from sinks, taps, etc
| Brown water=water from toilets.
