Construction Technology and Environmental Services Flashcards
1
Q
Which RIBA stage is on-site construction?
A
RIBA Stage 5 - Manufacturing and construction
2
Q
What is buildability?
A
- The extent to which the design of a building facilitates ease of construction
- Early contractor involvement should be considered to benefit from their experience and expertise
- Other benefits include lower capital and life cycle costs, better quality, programming, sequencing and construction methods
3
Q
Building works vs civil engineering works?
A
- Building works - all building types i.e. houses, offices, shops, hospitals
- Civil engineering works - drainage schemes, highways, bridges, retaining walls
4
Q
What site surveys might be required for typical construction project?
A
- Topographic survey
- Site investigation
- Asbestos survey
- Drainage CCTV
- Utility searches
- Ecological
- Flood risk assessment
- Transport assessments
- UXO discovery
- CBR test
- Archaeological dig / excavation
- Existing condition survey
- Geotechnical survey
- Structural survey
- Condition survey (similar to struct, more on building fabric-materials)
5
Q
Different types of survey?
A
- Desktop - looks at history of site and surrounding area to gain info
- Intrusive - site visit with investigation i.e. bore holes
6
Q
Main site considerations?
A
- Access
- Storage and accommodation
- Temp services
- Plant
- Hoarding / fencing
- H&S
7
Q
What is a CBR test?
A
California bearing ratio
- Tests load bearing capacity of ground, informs foundation design and construction details for other ground bearing elements (i.e. roads)
8
Q
What are the objectives of a site investigation?
A
- Primary purpose to establish parameters for foundation and substructure design
- Assess properties and composition of soil and rock, potential ground contamination
9
Q
Typical components of site investigations?
A
- Systematically collect and record data to help design / construction
- Adjacent site impacts
- Boundary hedges / fencing
- Existing trees, buildings
- Services location (gas, phone, elec, water, drainage)
- Ground water conditions
- Soil investigations
10
Q
Tell me more about soil investigations
A
- Determine suitability of site for proposed works to determine adequate and economic fdn design (depends on building type too)
- Determine potential difficulties
11
Q
How can location impact material choice?
A
Town centre not suitable for steel frame delivery
12
Q
What would you do if land is contaminated?
A
- Contact local authority and environment agency
- Further testing required to see if soil is suitable and project can go ahead
- Hazardous material needs to be removed from site and disposed properly
13
Q
Types of vegetation that can cause issues for construction project?
A
Invasive plants i.e. Japanese knotweed
14
Q
What surveys were undertaken on your project to inform foundation choice?
A
i.e. Geotechnical technical survey
15
Q
What are temporary works?
A
- Part of construction works not usually on drawings but are needed to enable permanent works to be built safely
- propping, scaffolding, formwork, excavation support
16
Q
What are hoists?
A
Designed for vertical transportation of materials and/or people
17
Q
What is shoring?
A
Form of temp support given to existing buildings and excavations. Prevent collapse / excessive movement
18
Q
What is scaffold?
A
- Temp working platform erected around building/structure perimeter to provide safe working place at convenient height
- Usually required for 1.5m+ above ground
19
Q
What is formwork?
A
Anything holding fresh in situ concrete in place until it hardens - plywood shutters, profiled decking, steel plan forms, fibreglass moulds
+ accessories i.e. wedges and clips for tightening joints and to make stripping easy
20
Q
What is a tower crane and how do you erect one?
A
- Tall crane used to lift objects to high places. Has boom allowing longer reach and 360 deg access, longer boom = less payload capability
- Use smaller crane to erect
21
Q
What would stop a tower crane from working?
A
Weather conditions, i.e. high strong winds
22
Q
What is a borehole?
A
- Used for soil investigation / geothermal heating solutions
- Most suitable soil investigation method when foundations 3+m deep
- Geothermal boreholes permanent - use Earth’s natural heat to raise temp of circulated water. Closed system used to heat building above - sustainable tech
23
Q
Main types of excavation?
A
- Open - battered excavation sides cut back to safe angle, eliminates need for temp support work, easily construct basement walls BUT extra excavation costs, needs a lot of space
- Perimeter trench - trench dug to form basement walls, supported as required. Basement walls constructed then inside excavated
- Complete excavation - firm subsoils, centre of basement excavated first, then basement slab cast while sides of excavation supported by struts
24
Q
Different forms of excavation?
A
- Site clearance (remove vegetation and rubble)
- Strip topsoil
- Reduced level dig (reach formation level)
- Cut and fill
- Excavation for foundations
25
Key factors to consider when excavating?
- Soil type, moisture content
- Method
- Whether ground support systems required
- Proximity of existing buildings
- Depth required
- Underground services and drainage
26
What is landfill tax?
- Brought in by UK govt 1996
- Helps reduce amount of waste landfilled, promotes reuse, recycling and research into waste practices
- Applies to all waste disposed of at licensed landfill site, unless specifically exempt
- 2 rates, £3.15/tonne inert, £98.60 all other
27
Where would you dispose of asbestos?
Approved HSE area, fully bagged up, signage on truck etc
28
What is substructure?
- All structure below superstructure, i.e. below ground level inc GF bed
- Transmits building load to the ground
- Foundations, basements, retaining walls etc
29
What is ground heave?
- Associated with clay soil (swells when wet), causes ground to move upwards
- Soil can't expand downwards / sideways -> exposed upper surface rises up
30
What are retaining walls?
- Earth retaining structure for whole / part of their height
- Purpose is to resist lateral pressure of soil with change in ground elevation
- Need to consider pressure of water and retained earth in design
31
Techniques available for ground improvement?
- Vibro compaction
- Vibro stone columns
- Vertical drains and vacuum consolidation
- Soil mixing
- Dynamic compaction
- Dynamic replacement
32
What is underpinning? Why might it be required?
- Method to repair and strengthen foundations
- Stabilises fdns undergoing settlement/movement/erosion/vibration damage
- Increase load capacity of existing fdn
- Accommodate new adjoining building, basement or deep sewer
33
Can you describe the substructure on one of your projects?
34
How have you been able to apply your knowledge?
- Producing estimates from early design stages, I have to apply my own knowledge to make reasonable assumptions of what would be most apt solution
- For example, I assumed xxx
- I undertook a cost analysis for different fdn solutions xxx
35
What is a foundation?
Function is to safely sustain and support superstructure, and transmit to ground the combined dead, imposed and wind loads of structure to avoid excessive settlement
36
Dead loads vs live loads on a structure?
- Dead - static forces, relatively constant for extended time (usually weight of materials)
- Live - dynamic forces from occupancy and intended use (inc people, furniture, appliances, moveable equipment)
37
Typical considerations when selecting type and size of foundations?
- Building load
- Nature and bearing capacity of ground
- Structure type
- Cost
- Construction constraints (proximity to nearby structures)
38
Different types of foundation?
- Strip
- Pad
- Raft
- Piled
39
Explain the suitability of different foundation solutions
- Strip - well-made ground with good load-bearing capacity, low load-bearing weight from structure
- Raft - poorly made ground with low load bearing capacity- spread load across entire building footprint
- Pad - well-made ground, for structures with high load-bearing points i.e. columns on steel frame
- Piled - High load-bearing, poor ground and tight sight conditions
40
Typical components in ext wall / foundation detail?
- Strip foundation
- Concrete block foundation wall
- Rebar reinforcement
- DPC
- Air bricks
- Suspended / GF slab
- Backfilling
- Drainage
41
Can you explain the foundation choice on xx project?
- i.e. built up area, soil quality, depth of potential bedrock, adjoining properties, structure type
42
What are pile foundations?
Pile = column (usually concrete) extending deep into ground
43
What are piles?
- Series of columns constructed / inserted into ground to transmit structure load to lower level of subsoil
- Used where no suitable fdn conditions near ground level / high water table, poor bearing capacity of soil
44
Main construction methods for piled foundations?
- Bored piles
- Driven piles
45
Different types of piles?
- Sheet - deep trench excavated and concrete poured insitu. Piles form basement walls / act as retaining walls
- Secant - Interlocking (male + female) piles of different diameter and hardness, solid barrier free of gaps- bored to provide combination of fdn and basement wall. Help provide waterproof structure. Used in top-down construction method / top form retaining walls
- Bored piles - auger used to excavate soil and concrete poured once complete. Variation is CFA (continuous flight augered) - piles are bored, bentonite slurry pumped in to stop core collapsing and concrete poured in. (Bentonite is environmentally harmful, not often used now)
- Pre-cast piles - brought to site and hammered into ground - high noise lvl and installation, lack of flexibility with depth
46
Different ways piles transfer load to the surrounding ground?
- End bearing - transfer load through low-bearing capacity soil to strong stratum (rock/dense sand)
- Friction - frictional resistance between outer surface and soil in contact
- Settlement reducing - beneath central part of raft foundation to reduce differential settlement to acceptable level
- Tension (tall chimneys, transmission towers, jetties) - resist uplifting forces that may otherwise cause structure to be extracted from hydrostatic pressure, seismic activity or overturning movement
- Laterally loaded piles - bridge piers, tall chimneys, retaining walls
47
How do end bearing piles transfer the load of the building?
- Bottom of the pile rests on layer of strong soil / rock
- Building load transferred through pile to strong layer
48
How do friction piles transfer the load of the building?
- Pile-bearing capacity by shear stresses along side of pile
- Surface of the pile works to transfer the forces to the soil
49
When would you use a bored pile? What's the process involved?
- Build up areas with cohesive soils (i.e. clay) with requirement to go down 15m+
- Used where load requirement greater than CFA capabilities - larger diameter, greater depths
- Heavy duty crane with Kelly bar, concrete mixer truck and bentonite storage. Soil excavated, bentonite and casing inserted to stabilise, concrete pour with mixing truck and reinforcement cage, casing removed on completion
50
Bored pile vs CFA pile
- Bored piles have excavation and concrete pour done separately, crane + more substantial piling rig, larger diameter and greater depths, casing required
- CFA - concrete pour done as auger pulled out
51
Bored vs pre-cast (/ driven) piles
- Bored - removing spoil to form hole is carried out by boring technique. Cohesive soils for friction piles and when forming fdn close to existing buildings is limited
- Pre-cast - soft soil deposits overlie firmer stata - usually driven using drop / single action hammer
52
Advantages and disadvantages of driven / precast piles?
Advantages
- Can be precast to required spec
- Any size, length and shape can be made in advance
- Driven into granular soil compacts adjacent soil mass -> bearing capacity can increase as a result
- Fast, neat and clean installation
Disadvantages
- Requires heavy equipment to handle and deliver
- Increased noise and vibrations
- Costly if piles are too short
53
Advantages and disadvantages of bored piles?
Advantages
- Any size / shape can be formed on site
- No risk of damage during delivery and handling
- Less vibrations and noise
Disadvantages
- Significant spoils generated - need to be handled
- Reliance and coordination on multiple trades (reinforcement, piling and concrete crews/suppliers
- Don't improve bearing capacity of ground
54
QS problems regarding cost control with piling?
End depth never a certainty
55
Whose risk is piling?
- D&B and traditional - main contractor
- Management - employer
56
Where would piled foundations be the best solution?
- Heavy structure, weak underlying soil
- Settlement issues common in area
- High sub-soil water table
- Load distribution of structure not uniform
- Horizontal forces present
57
What is a raft foundation?
- Continuous slab extending over entire footprint of building
- Spread load of superstructure over large base, reduce load per sqm of area
- Useful in load bearing capacity soils and heavy individual column loads
- Solid raft slab / beam and slab raft - ground beam system and suspended PC concrete GF
58
What conditions are required where you'd expect a raft foundation?
- Lightly loaded buildings, poor soils
- Heavy loads can cause raft to move sideways (as it's not very deep)
59
What is a strip foundation?
- Formation in strip of linear structure, spreading weight across total ground area (supports masonry)
- Suitable for most subsoils and light structural design
- Usually reinforced
60
What are pad foundations?
Provide a base for reinforced concrete / steel columns. Usually constructed from reinforced concrete, square / rectangular on plan
61
What is a basement?
Storey below ground storey
62
3 types of basement construction?
- Retaining wall and raft (monolithic) - slab raft foundation, basement walls are retaining walls
- Box and cellular raft - similar to above, internal structure walls transmit and spread loads over raft, divides basement into cells
- Piled - main superstructure loads carried to basement floor by columns, transmitted to ground via pile caps, bearing piles (lots of columns going through basement)
63
3 methods of waterproofing a basement?
- Dense monolithic - designed and built to form watertight space using high quality reinforced concrete, needs strict control and good workmanship
- Tanking (i.e. polythene sheeting, bitumen, epoxy resin), applied internally/externally to provide continuous membrane to base slabs and walls. External better as this protects structure too
- Drained cavity - can be used for new / refurb work. Accepts small water seepage levels, collects and drains away. Inner non-load bearing wall to form cavity, floor laid to falls, moisture drains to sump, discharged direct
-> waterproofing solution often influenced by basement final use
64
Different grades for waterproofing basement?
- Grade 1 - some water seepage and damp is tolerable (i.e. car parks)
- Grade 2 - No water penetration acceptable
- Grade 3 - No dampness / water penetration acceptable (i.e. ventilated resi and commercial areas - homes, offices, shops)
65
What is superstructure?
- All internal and external structure above substructure / DPC
- Primary elements - ext walls, stairs, roof, struct walls
- Secondary elements - suspended ceilings, raised floors, balustrades, doors
- Finishes - tiles, paint, stair nosings
66
Describe external wall build up on one of your projects?
i.e. SFS, vapour control layer, cement particle board, 80mm insulation, aluminium facing bracket
67
What is the external envelope?
- Materials and components forming external shell / enclosure of a building - boundary between interior and exterior
- May be load or non-load bearing
- Typically consists of brickwork, cladding, curtain walls
68
What is a retained facade?
- Facade retained whilst everything behind front wall demolished
- Allowance needed for temp support and cleaning/restoration works
- Often for listed buildings
69
Key considerations designing external walls?
- Weather protection
- Fire resistance
- Acoustic, thermal and structural performance
- Aesthetic / appearance
- Lifespan
- Future maintenance
70
What is a curtain walling system?
- Typically, lightweight aluminium frame, with glazed / opaque infill panels fixed to it
71
Different cladding options?
Timber, aluminium, brick, slip, PCC, glazed, stone
72
What is a movement joint? Why are they used?
- Safely absorb expansion and contraction of construction materials
- Allow for movement associated with ground settlement, seismic activity
73
In brick/block cavity wall, how are window openings dealt with?
- Prevent water penetration - cavity tray (DPC crossing cavity, forming gutter leading to weephole in outer leaf) and DPC (same width as wall to stop moisture rising from the ground up external leaf of wall
- Structurally - Lintel, small beam over window / door head usually carries wall load only
74
What is rain-screen cladding?
- Cladding manages flow of rainwater on building
- Not necessarily waterproof itself
- Serves as screen and protection against rain for rest of building
75
What is rainscreen cladding used for?
- Exterior surface to break force of sideways, wind-driven water movement
- Most water bounces off/runs down, any that gets through loses momentum
- 2 key system types: drained & ventilated, pressure-equalised
76
How is composite metal cladding fixed to a steel frame?
Bolted, riveted, welded
77
What is a cladding stick system?
- Curtain wall frame (mullions) and glass/opaque panels installed and connected piece by piece
- Versatile, allows integration of other systems (sliding doors, windows)
- Less specialised, can be build by all types of fabricators
- Multiple steps to erect and seal wall, more time spent on site (70% on site vs 30% in factory), additional labour time
78
What is a unitised cladding system?
- Narrow width, storey-height aluminium framework units containing glazed/opaque insulated panels
- Entire system pre-assembled under factory controlled conditions
- Unitised panels craned into position- pre-positioned brackets attached to floor slab / structural frame
- Modern techniques increase speed of erection and minimise scaffolding requirement
- Unitised systems have higher direct costs (despite lower labour)
79
Stick vs unitised cladding system
- Stick - constructed onsite, transoms and mullions (vert and horiz respectively) made from aluminium, connected together on-site to floor slabs
- Unitised - Component parts constructed off-site - pre-fab units delivered to site and fixed straight to building
80
Benefits and limitations of stick and unitised
cladding systems?
Stick
- Lower cost, flexibility due to on site construction
- Longer to erect on site, requires more labour, less quality control
Unitised
- Erected on-site in 1/3 of time, better quality control, achieve more complex design
- Higher cost, risk of mistakes during fabrication affect installation on site
81
What are panelised systems?
- Constructed in factory (better quality control and speed of erection
- Large prefabricated panels of bay width and storey height, connected to primary structural columns / floor slabs
- Panels may be precast concrete / have structural steel framework clad with stone, metal and masonry materials
- Improved adherence to spec, quality control, rabid insulation, min. no. site sealed joints
- Less common, more expensive than unitised
82
What other elements are affected by the type of cladding systems used?
Frame, roof, M&E
83
Types of curtain walling?
- Stick - panels / glazing in between transoms
- Unitised - narrow storey height units, preassembled in factory
- Panelised - large preassembled panels connecting back to structural columns
- Structural glazing
84
When have you advised on the frame option?
Would be subject to structural engineer, however on similar projects I used xxx
85
Frame construction methods?
- Steel
- Concrete
- Timber
- Hybrid (i.e. CLT)
- Load bearing masonry
86
Key factors to consider when selecting structural frame type?
- Programme
- Fire protection
- Acoustic and thermal properties
- Market conditions, supply costs
- Site constraints/logistics
- End user requirements (i.e. column free space)
- Sustainability objectives
- M&E strategy
- Future expansion requirements
87
Components of steel frame construction?
- Beams, columns
- Purlins
- Rafters
- Eaves, eaves haunch
- Base plate
- Apex haunch
- Cladding rails
- Fixings
88
Steel frame advantages?
- 100% recyclable, won't warp, crack, split, nor be vulnerable to termites / organisms
- Highest strength:weight ratio
- Dimensionally stable - won't expand / contract depending on weather conditions
- Consistent material quality, strictly produced in accordance with national standards, no regional variations
- Non-combustible- won't contribute to spread of fire
- Lighter- in poor soil conditions steel is preferred to concrete
- Faster to install than concrete
- Can span over long distances
- Manufactured on-site - quality benefits
- Voids within floor can run services
- Suitable for irregular shaped buildings
89
Steel frame disadvantages?
- May need fire protection
- Although they don't burn, they fail (collapse) before wood component in fire
- Parts may need replacing
- Variable cost
- Experienced builders required (+ cost)
- Lower load bearing capacity vs concrete
- Don't have same acoustic / thermal properties of concrete frame
- Prone to corrosion in coastal areas
- High embodied carbon (often procured from abroad)
- Long lead-in times - Letter of intent / materials off site may be required
90
Different parts of steel beam?
Flange - top and bottom of vertical steel
Web - vertical steel part of I
Root - where flange and web join
91
What is a steel table?
Table providing std info on steel sections in tabulated form - serial size and universal beam number
92
Weight of steel?
10mm3 = 0.0078kg
93
What is powder coating?
- Durable factory applied organic coating on metals, i.e. polyester, acrylic, epoxy, sprayed on, followed by heat curing to give film thickness 50-100microns
- Any holes/cutting to be done before coating applied
94
What is RHS / SHS?
Rectangular / Square Hollow Section
95
What is intumescent paint?
- Fire-resistant paint, passive fire protection system
- Rapidly expands in extreme temps to protect surface it's applied to
- Prevents/minimises/delays structural fire damage
96
How do you apply intumescent paint?
Sprayed on in factory, touched up by hand on site
97
Steel connections and percentage?
Plates, bolts, welding
5% by weight
98
What is a portal frame? What type of buildings are they suitable for?
- Beam / rafter supported at either end by columns
- Columns typically connected to rafters (haunch/eaves connections)
- Long clear spans - large areas of open space
- Commonly used for warehouses, factories
99
Concrete frame advantages?
- Concrete framed buildings marginally less than steel framed buildings
- Fire protection is part of structure
- Slower - reduces cashflow early on
- Low maintenance
- Cladding easily fixed to concrete and replaced
- Good sound and heat insulation
- Insitu allows alteration at late stage of construction
- Complex geometrical shapes easier dealth with than steel
- High compressive strength
- Lower embodied carbon - can be made with by-product of coal and iron industry
100
Concrete frame disadvantages?
- Slower to construct, inc long curing time
- Requires formwork
- Edges may not be as square / surfaces not as flat as steel
- Steel reinforcement leads to cost issues associated with steel
- Heavier -> larger foundations
- Bulkier structure
- Doesn't span as well as steel
- Low tensile strength
- Higher floor height required to accommodate services
- In-situ quality dependant on skill of operatives
101
What is formwork (in relation to concrete frames)?
- Usually temp structure to contain poured concrete and mould to required dimensions
- Stripped away after hardened and can support itself
102
Timber frame advantages?
- Faster construction on-site vs in situ concrete
- Relatively lightweight structure
- Aesthetically pleasing
- Sustainability benefits (assuming timber harvested responsibly)
103
Timber frame disadvantages?
- Skilled workmanship required for high-quality finish
- Potential for wet/dry rot, woodworm
- May require fire protection
104
Elements of a pitched roof?
- Rafters, battens, eaves, fascia, soffit, gutter, joist, ridge, ridge board, hanger, membrane, tiles
- Vent tiles may be used to provide natural ventilation to roof space
105
What is an upstand? / Describe a typical parapet wall-roof abutment detail?
- Vertical strip / skirting (weatherproofing) where roof meets abutment wall (extending above roof level)
- Roofing itself (particularly or mastic asphalt), top part of 1-piece apron flashing, mortar skirting, upstand flashing / waterproofing detail, DPC closer above flashing and at head of wall under coping
- Either stepped, raking, or level
106
Main components of hipped end timber roof structure?
- Principle rafters (support to roof covering, eaves to ridge)
- Jack rafters (shorter rafters, hip to eaves / ridge to valley)
- Ridge board (spine of roof carcass along ridge)
- Wall plates (receive feet of rafters at top of external wall)
- Hip rafters (where 2 roof surfaces meet, form ext angle)
- Valley rafter (where 2 roof surfaces meet to form internal angle)
- Bargeboards / fascia (to cover feet of rafters)
- Purlins (intermediate horizontal members supporting rafters)
- Battens (small pieces of wood which roof covering is affixed)
107
Elements of a flat roof?
- Joists (fixed to wall plates- main support)
- Furrings (fixed to joists to give required incline)
- Particle board (fixed to furrings to give flat surface)
- Felt (3 layers bonded with bitumen to give waterproof covering)
- Stone chipping (gives protection to felt, reflects sunlight)
108
Different types of roof coverings?
- Single layer membrane - one layer of felt consisting of base sheet of glass fibre/polyester, impregnated with hot bitumen during manufacture
- Built up membrane - 3 layers of above felt, 1st laid at right angles to fall, next is perpendicular, and again for third layer. Covered with stone chippings
- Asphalt - Aggregate with bituminous binder cast into block. Reheated onsite at 200deg, transported as liquid to roof. Usually 2 coats
109
Advantage and disadvantage of single layer membrane?
Cheapest option, but too thin, easily punctured and rarely used
110
Advantage and disadvantage of built up membrane?
More durable than above, but can be easily punctured without proper care
111
Advantage and disadvantage of asphalt?
- Reduced risks of defects (poured on site, not in rolls which may be damaged in transport), hard wearing, can allow transit on top, can have long life guarantee
- Hot temperature - apt H&S measures required
112
Describe typical cold flat roof construction
- Insulation above ceiling level - between roof joists and below roof deck
- Risk of condensation forming within roof void / on underside of slab - good cross centilation essential
- Plywood decking secured to joists and finished with roof covering
113
Describe a typical warm flat roof construction
- Insulation on top of roof deck, beneath waterproof membrane
- Vapour control layer under insulation
- Reduces risk of condensation as ceiling / roof void at similar temp
114
Cold vs warm flat roof?
- Insulation position varies
- Warm - between roof rafters, above roof level (warm roof)
- Cold - insulation above ceiling (warm house)
115
Describe a typical inverted flat roof construction
- Insulation on top of waterproof membrane - anchored down, protects membrane from damage
- No vapour control required
- Roof void and deck maintained at similar temp to room
116
Green vs blue roof?
- Green - absorbs rainwater, habitats wildlife, aesthetics, helps lower urban air
- Blue - collects water and releases slowly after rain's stopped, e.g. attenuation tank
[both are forms of SUDS]
117
Purpose of a parapet?
- Extension of ext bldg shell above roof level
- Used as edge protection to enable maintenance to take place
- Mask unsightly roof plant from GF level
118
Gable vs hipped vs mansard roof?
- Gable - Roof sloping down in 2 parts from central ridge (monopoly house)
- Hipped - Roof sloping upwards from all sides, no vertical ends
- Mansard - Steep front face pitch with shallow pitch/flat roof on top
119
What is a mansafe fall arrest system?
- Horizontal / vertical safety lines (stainless steel wire rope)
- Keeps people safe whilst working at height (they use safety harness and clip onto lime
- Limits distance and consequence of a fall
120
What would you expect to find on timber / part glazed door with FR30 requirement?
- 3 hinges
- Intumescent strip
- Self-closing device
- Part glazed door - 6mm thick, wired to max 1.2sqm with 13x13mm wood beads encased with non-combustible materials
121
What is power floated and why?
Concrete, maintain flatter surface when applied at faster rate
122
What are the different types of screed?
- Bonded - laid to rough, cleaned concrete base
- Unbonded - laid to sound, clean, bitumen DPM
- Floating - Laid with steel / fibre reinforcement onto insulating board, can be laid onto DPM
- Resin bonded - laid onto clean, rough pre-prepared concrete base. Resin acts as DPM to top screed
123
What are main factors that might affect the choice materials for internal partitions?
- Strength - if fixings required
- Level of transparency required
- Acoustic and fire rating
- Fixed / movable
- Thermal properties
- Door/window requirements
- Height
124
Different types of partition available?
- Timber (usually for housing)
- Steel stud (larger schemes)
- Block (struct components - riser, lift shafts)
- Glazed internal screens
125
Partition build up?
- Head and base track
- Stud fixed at 600mm centres (plasterboard typical width 1200mm)
- Insulation between studs
- Pattressing
- Door openings formed
- Abutments, tees, fair ends
- Plasterboard
- Head detail (depends on frame)
126
How do you construct a glass partition?
- Glass fixed into frame (wood / steel)
- Glass placed in a rebate, secured with putty / beading
- Frame mounted between walls / columns required, usually secured with putty
127
Categories of office fit out?
Shell and core, CAT A, CAT B
128
What is shell and core?
Elements inc substructure, superstructure, core services (up risers to plant only), external envelope of building constructed to create 'shell' for developer fit out
129
What is CAT A fit out?
- Basic level of finish, i.e. raised floors, suspended ceilings and partitions, basic M&E services
- Bare-bones / blank canvas for interior designers
130
What is CAT B fit out?
- Provides space ready to move into and operate
- Can inclue partitions and doors, floor finishes, specialist lighting and facilities, cafes, tea points, kitchen areas, furniture, branded material and decor
131
What is the purpose of a threshold strip?
- Light rounded metal strip over joint between floor finishes / coverings meeting under door leaf
- Prevents fraying, looks better, interrupts combustible flooring under fire doors
132
What is an MF ceiling?
Mineral fibre plasterboard suspended ceiling
133
What is a metal grid ceiling - what are the benefits?
- Suspended ceiling formed by square grid
- Quicker to construct, allows surfaces to run through void, easy access for service / repairs, easily repair damaged tiles (not whole ceiling)
134
Difference between rolled and tiled carpets? Why use each type?
- Rolled - better quality, more expensive, used in dwellings
- Carpet tiles - harder wearing, lower quality, cheaper- individual tiles can be replaced (easier to maintain), easier access to services in raised flooring systems. Used in offices, hospitals, etc.
135
What is raised access flooring?
- Floor sitting on pedestals above structural slab
- Allows services to be located within void (power and data cables)
136
What types of board would you apply to partitions?
- Plasterboard (see materials section) - acoustic, mega decko, moisture resistant, fire rated, standard
- Can be plaster skimmed / tape and jointed
137
Rainscreen vs curtain walling
- Curtain walling - non structural building cladding
- Rainscreen - fixed onto frame of building
138
What is a BMS?
Building Management System- controls / coordinates lighting, heating, ventilation to achieve optimal conditions with minimal energy usage. Controlled via head end unit
139
How do you improve NIA / GIA based on M&E?
Services in ceiling void / under RAF instead of around perimeter
140
Types of ventilation?
Mechanical and natural
141
What is natural ventilation?
- Method of supplying fresh air to building / room via passive forces, i.e. wind speed, pressure
- Reduced carbon emissions key benefit
142
What is mechanical ventilation?
- Intentional fan driven flow of outdoor air into building
- Can include supply and/or exhaust fans
143
What is an air source heat pump? How does it work?
- Takes heat from air, boosts it to a higher temp using compressor
- Transfers heat back to heating system
- (like the reverse of a fridge / air conditioner)
- Can also have a split ASHP - system put in reverse to provide cooling
144
Main types of air conditioning system available?
- Refrigeration Cycle - Heat pump transfers heat from lower temp source to higher temp heat sink. Heat naturally flows in opposite direction. Most common type (works similar to refrigerator)
- Evaporative Coolers - Device draws outside air through wet pad. Sensible heat of incoming air as measured by dry bulb thermometer is reduced. Some of the sensible heat of entering air converted to latent heat by water evaporation in wet cooler pads. Coolers cost less and are mechanically simple to understand and maintain
- Absorptive Chillers - Gas turbines exhausts in buildings hot enough to drive absorptive chiller producing cold water. Water run through radiators in air ducts for hydronic cooling
145
What does HVAC stand for?
Heating, Ventilation and Air Conditioning
146
What does FCU stand for?
Fan coil unit
147
What does AHU stand for?
Air handling unit
148
What is a VAV?
- Variable air volume system (AC system)
- Controls flow of air
- Vary airflow at constant temp to meet rising and falling of heat gains within thermal zone being cooled
- Utilise supply duct distributing cooled air
- Made up of supply and return ductwork
149
What is a VRF? / What can be used to provide cooling in localised part of building?
- Variable refrigerant flow (AC system)
- Controls refrigerant flow to each FCU
- Heat pump system - can provide simultaneous heat and cooling
- Heat pump connected to indoor units
- Energy recovered from 1 zone can be used to heat separate zone
- Less space than traditional ductwork, more efficient compared to other systems
150
What is a VRV?
Variable refrigerant volume
- Controls temp by controlling volume of refrigerant
151
How does a 2 pipe system work?
Either heating or cooling, pipework supplied to individual fan coil units- treat air and supplies space via diffusers
152
How does a 4 pipe system work?
Heating and cooling, return and flow pipework from central heating, chiller plants supplied to CVUs. FCU supply either warmed / cooled via air diffusers
153
How are chilled beams constructed?
Passive
Ductwork under RAF, floor diffuser introduces fresh air slightly above room temperature. Hot air rises through perforated ceiling, chilled water throughout beams. This water cools hot air. Extract ductwork in ceiling removes stale air
Active
Chilled beam delivers fresh air and cools simultaneously. Cold water pipes connected to chiller plant located in ceiling soffits exposed to air in room. Cool air drops, warm air rises and is cooled and recirculated by exposed cold water pipes, extract ductwork in ceiling to remove stale air
154
Limitations of chilled beams?
Air in room must be exposed to ceiling- can't have a suspended ceiling system
155
What is hybrid ventilation?
- Combination of mechanical and ventilation
- Natural - automatically controlled windows
- Mechanical - supplements when required
156
What is MVHR? How does it work in a residential building?
- Mechanical ventilation heat recovery
- Pipework brings air to unit (usually via louvre on balcony wall), treats air and distributes unit
- Extract removing stale air from unit
- Can sometimes provide cooling element
157
How do fan coil units work?
- Fan blows air over warm/cold pipework
- Ducts bring treated air to diffusers
158
How does CHP work?
- Central heating plant with large boiler / chiller with return and flow pipework
- Heat interface in each unit transfers energy to pipework, supplies to radiators
159
Underfloor heating vs radiators?
UFH covers floor area- more energy efficient
160
Benefits of ground source heat pump?
Energy in ground is constant- reliable source
161
Issues with water source heat pumps?
Usually large distance from water source to plant room - high costs for the conduit/ducting
162
Open vs closed loop system?
- Closed - water recirculates in system
- Open - water in system replaced
163
What is CHP?
- Combined heat and power- generated power usually gives heat waste, CHP captures escaping heat to recover power
- Can't be stored- must be used immediately
164
When would you use CHP?
District heating system, i.e. resi block
165
Single vs 3-phase electrical supplies?
- Single phase = 1 live wire
- 3 phase = 3 live wires -> more consistent reliable current
- Both have neutral and earth wire too
166
What is a 3 phase electrical supply?
- AC supply with 3 AC voltages 120deg out of phase with each other
- Cheaper and easier way to transmit electricity vs single phase
167
Why do we stall generators in addition to regular grid power?
- Powered by diesel engines - backup power supply if primary one fails
- Generators becoming less common as technical advances being made in UPS
168
What is a UPS? Why might the client require one?
- Uninterruptible Power Supply
- Alternative 'no-break' elec supply where important to not lose elec supply
- Typically in hospitals - life-critical equipment, data centres, IT server rooms
169
How is power distributed to floor boxes in raised floor?
- Incoming power supply connects to low voltage switchboard, connects to a distribution board
- Dist board has underfloor busbar connected - busbar has sockets which floor box plugs are put into via flexible lead
- Floor box has sockets to which appliances can plug costs
170
What is CAT II Lightning?
Light fittings suitable for use with VDU screens- designed to limit glare from computer screens
171
Different types of lift?
- Passenger - specialised for service they perform (i.e. hospitals with front/rear entrances)
- Residential - Small enough for 1 person, some can be for 12+
- Platform - Wheelchair/platform lifts- specialist, designed to move wheelchair <2m. Accommodate 1 person, max load 340kg
- Freight - Similar to passenger lifts, but designed to carry goods (though there'll still be passengers so building regs still apply). Larger, capable of carrying heavier loads - 2300-4500kg. Manually operated doors, hydraulic freight / electric options (latter is more energy efficient)
- Dumbwaiter - Small freight elevator often for moving small items (i.e. in 2-storey kitchen). Small electric motor with counterweight or can be hand operated, capacity about 340kg
172
What is utility easement?
Legal agreement giving utility company access to use property
173
How to form a highway?
- Break out existing
- Excavating
- Capping
- Sub-base (100-250mm)
- Base (70-150mm)
- Binder (50-100mm)
- Surface/wearing course (20-40mm)
- Road restraint systems
174
Flexible vs rigid paving?
- Flexible - subbase, base, binder, surface course. Initial cost lower, less curing time, lower repair costs. Less durable, higher maintenance costs
- Rigid - subbase, concrete slab (less thick). More durable, low maintenance costs, no good subgrade required. High initial and repair cost
175
What is a culvert?
Tunnel-like structure, allows water to flow under a road, railway etc.
176
What is the purpose of a drainage headwall?
- Headwall = small retaining wall/structure at inlet/outfall of storm drainage pipe
- Protect end of drain and protect watercourse embankment from erosion
177
Have you come across the term SUDS?
- Sustainable Urban Drainage System
- Manage stormwater locally (close to source as possible) to mimic natural drainage, encourage infiltration and/or attenuation
- Help reduce reliance on existing drainage infrastructure
178
How does a siphonic drainage system work?
- Alternative to gravity drainage system - water sucked from guttering to drainpipe - no need for pipes, relies on gravity to pull water to drain
- Anti-vortex plate acts as baffle, prevents air/debris entering piping system at full flow - pipes completely fill up with water
- Water sucked from roof down to drain at high velocity - fast and efficient
- Narrower down pipes can be used
179
What are the benefits of off-site construction vs in situ?
- Safety - hazards i.e. falls from heights more likely onsite vs factory
- Controlled environment - efficient and quality control
- Sustainability - reduction in waste
- Speed - work in factory can be done simultaneous to other activities on site
180
Different types of MMC?
- 7 categories - struct in cat 1-4, non-struct in 5-7
1 - volumetric 3D boxes
2 - large 2D panelised systems (i.e. CLT)
3 - 2D small (PCC columns, slabs, stairs)
4 - adaptive manufacturing 3D printing
5 - non-struct modern methods- pre-fab bathroom pods, kitchens, M&E sledges
6 - material, QR codes, logistic tracking
7 - labour, QR codes and tracking
Modular (entire building like lego bricks)
Volumetric (pre engineered units incorporated to trad build - bathroom pods)
Panelised (individual elements assembled on site, i.e. curtain walling)
Component (smaller parts, door sets, roof trusses, stairs)
181
Where is MMC suited?
- Cat 1 - time takes precedent (hotels, NOT housing)
- Cat 2 - all construction - housing usually sold off plans
182
QS MMC considerations?
- Costs more, potentially working on different sites, prelims costs
- More suited to milestone payments, vesting certificates, advance payments, materials storage
- Small pool of MMC contractors, lack of benchmarking data available
183
CLT construction details? Benefits and limitations?
- Small sections of timber bonded with permanent adhesives, forms panels. Bonded perpendicular to one another
:) most finishes can be applied straight onto it, renewable material, airtight envelope, lightweight, can be constructed off-site, reduces load on foundations
:( complete design before start onsite, accurate setting out required, external cladding needs to provide waterproof envelope, compressive strength less than concrete and steel
184
Advise on time/cost/quality of different materials and methods of construction?
On xxx project, although higher upfront cost, longer life span and reduced maintenance and repairs costs, reduced programme
185
What are Building Regulations?
- Min performance standards for design and construction of buildings, supported by Approved Docs and other codes of practice
- Regulations ensuring new buildings, conversions, renovations, extensions will be safe, healthy and high-performing
- Cover specific topics, inc structural integrity, fire protection, accessibility, energy performance, acoustic performance
186
Why do we have building regulations?
- Establishes min stds and guidance on construction elements
- H&S
- Enables mortgages and insurances to be granted
187
What type of building work is covered by Building regulations?
- Erection / extension of building
- Extension of service controlled by regulations
- Alteration projects with temp/permanent effect on building - structure, fire and access
- Insertion of insulation into cavity walls
- Underpinning building foundations
188
Process for building control sign off?
- Building notice submitted to local planning authority - small projects
- Full application (drgs and spec submitted) - BCO visits site and inspects works, larger new build projects
- Local authority / approved inspectors will come to sign off
189
Alternatives to building control?
- BREEAM - either client preference/imposed as planning condition
- British Standards - recommentations for min material standards
190
What are British Standards?
- Publications issued by British Standards Institution, prefixed BS
- Give min standards for materials, components, design and construction practices
191
What are international standards?
- Prepared by International Organisation for Standardisation, prefixed ISO
- Compatible with and complement BS' (i.e. ISO 9000 is quality)
192
What are the Building Regulations approved documents?
- General guidance on performance of materials, to comply with functional requirements of building regulations - practical examples
- Only guidance, no obligation to adopt specific solutions if requirements can be met via alternative means
Part:
- A - Structure
- B - Fire Safety
- C - Site preparation
- D - Toxic substances
- E - Sound resistance
- F - Ventilation
- G - Sanitation, hot water safety and water efficiency
- H - Drainage and waste disposal
- J - Combustion appliances and fuel storage system
- K - Protection from falling, collision and impact, opening and cleaning
- L - Conservation of fuel and power
- M - Access to and use of buildings
- N - Glazing - safety in relation to impact, opening and cleaning
- P - Electrical safety
- Q - Security - dwellings
- R - Physical infrastructure for high-speed electronic communication networks
- S - Infrastructure for charging electric vehicles
- Regulation 7 - Materials and workmanship
193
Changes to building regulations?
Part B Fire safety - sprinkler systems and emergency wayfinding signage
194
Who reviews design and construction phase for compliance with Building Regulations?
Building control officer / approved inspector
195
Who ensures the building regulations are complied with?
Building Control Services - i.e. Local Authority / Approved Inspector
196
Are there other forms of legislation (in relation to resi)?
National House Building Council (NHBC) - acts like building control requirement for individual units
- Requirement for insurance and mortgage purposes
- Housing Act 2004
197
What is BREEAM?
- Building Research Establishment Environmental Assessment Method
- Assessing, rating and certifying sustainability of buildings
198
Alternatives to BREEAM?
- LEED (Leadership in Energy and Environmental Design)
- SAP (Standard Assessment Procedure for energy rating of dwellings)
- Code for sustainable homes
199
Name some materials banned from use in construction?
- High alumina cement in structural elements
- Asbestos
- Urea formaldehyde
200
How does the Equality Act affect buildings?
- Requires 'reasonable adjustments' to be made when providing access to goods, facilities, services
- More broad obligations than Part M requirements
201
What is the Party Wall Act 1996?
- Framework for preventing and resolving disputes related to party walls, boundary walls and excavations near neighbouring buildings
- Separate to obtaining planning permission / building regulations approval
202
What are O&M manuals? What might be included?
- Operation and Maintenance manuals - contractor produced, issued to client / building owner upon completion
- Inc info relating to how building has been constructed, should be maintained, cleaned and decommissioned, as built drawings and specifications
203
What safety provisions would you expect to find in an office block?
- Max. occupancy listings
- Fire exits - signage above that function in power failure
- Fire extinguishers and alarms easily accessible
- Restricted use of flammable materials
- Fire alarm control panels - quick detection and warning of fire
204
Design considerations for disabled access?
- Wide enough corridors
- Fire evac - refuge points, evacuation slide
- Access ramps
- Door access
205
Regulations governing accessibility?
- Equality Act 2010 (s/s disabled disability act 1995)- Important for local authority projects
- Part M
206
What impacts did COVID have on construction?
- Construction leadership council published site operating procedures
- Social distancing, risk assessment methods, methodology for task involving more than 1 person, hygiene
207
How do CDM regs affect construction?
- Design must have H&S considerations
- Projects may be notifiable
- F10 - notifying 20+ operatives on site at 1 point, 200+ hrs, 30 day+ programme
208
How does the Energy Act 2011 affect construction?
Energy efficiency requirements - smart meters, replacing inefficient boilers, PV and low carbon zero technologies
209
Different types of planning applications?
- Full (whole detail)
- Householder extension
- Outline (masterplan)
- Reserved matters (RMA)
Everything must be discharged within time frame. Restrictions on times
210
BCO vs approved inspectors
BCO = straight from the local authorities
Approved inspectors = private sector individual / body designated by local authority
211
What are the main components of concrete?
Cement, aggregate, water
212
What is pre-tensioned concrete?
- Reinforcement (tendons / cables) stretched across concrete formwork before concrete is placed
- Tendons attempt to shorten and transfer energy stored to concrete
- Compressive force induced into concrete
213
What is post tensioned concrete?
- Concrete cast around ducts/sheathing to house tendons
- Stressing carried out after concrete cured, by hydraulic jacks
- Used when stressing required onsite after casting in situ element / when PCC units joined together to form required member
214
What is A182 mesh?
Mesh used to reinforce concrete slabs, laid down and concrete poured over it
215
What is reinforced concrete?
Concrete with reinforcements (steel bar, rods or mesh) -> improves compressive strength of concrete and tensile strength of steel -> resistant to more types of loading
216
Different parts of a steel beam?
I beam:
- Flange (top and bottom of vertical steel)
- Web (vertical steel part of I beam)
- Roof (where flange and web join)
217
Size of a brick?
Standard - 215 x 102.5 x 65mm
218
What is the frog and which side does it go on?
- Indentation on one of the bed faces of brick, usually the top
- Unless specifically stated, bricks laid frog facing up, mortar filling the frog
- Gives stronger wall and superior sound insulation
219
How many bricks per sqm?
~ 60
220
How many UK std size blocks per sqm?
~ 10
221
Different types of brick bond?
- Stretcher - most common half brick thick, vertical joints staggered each time by half a brick
- English - alternating courses of headers and stretchers
222
What is an air brick?
- Perforated brick allowing for ventilation in room or underfloor space
- Not a weep hole
223
What is a weep hole?
- Small opening in outer skin of masonry construction
- Provide ventilation to cavity, allow moisture to drain away
224
Name some sustainable construction materials
Biodegradable materials, solar power
225
What is a glulam beam?
- Glue-laminated timber
- Multiple layers of solid wood bonded with high-strength adhesive, forming single structural unit
226
Common types of plasterboard?
- Standard (white/light grey)
- Fire boards (pink)
- Acoustic (blue)
- Moisture resistant (green)
227
Name some deleterious materials
- Lead (flashings on roofs - waterproofing)
- Asbestos (insulation)
- Brick slip systems
- Woodwool slabs (ceilings)
- High alumina cement (used a lot in 60s, 70s)
- Sea dredged aggregates (high chloride content)
228
Different types of asbestos?
- Chrysolite (white) most common least dangerous
- Amosite (brown)
- Crocidolite (blue)
229
What is scabbling?
- Utilises piston driven carbide-tipped heads hitting surface at rapid rate to pulverise concrete / brittle coatings
- Useful to remove slightly bonded coatings / where shot blasting won't work
- Remove level inconsistencies in concrete floors
230
What is slip forming?
- Method for constructing repetitive structure i.e. core, lift shaft, stairwell
- Formwork constantly moving up, approx. 1 inch every 10 mins
- Exposed concrete must be cured enough to support
231
What is jump forming?
- Significant height of concrete cast and left to cure
- Whole formwork module moved up and repeated
- Similar to slip forming but slower and cheaper process
232
What is top down construction?
- Allows superstructure and basement to be built simultaneously. GF slab constructed, below ground excavated
- More expensive generally - specialist plant and complex methodology
233
What is bottom up construction?
Traditional method, basement and substructure elements constructed then working upwards. Simpler, but longer programme
234
Typical programme for new build structure?
- Site clearance
- Enabling works
- Site setup
- Haul & access roads
- Setting out
- Excavation
- Foundations
- Frame
- Cladding
- Roof
- Floors
- Services
- Finishes
- FF&E
- Testing and commissioning
- Landscaping
- Snagging
235
What to consider for life cycle costing? (LCC)
Present value, life span, maintenance costs, cleaning and operation costs
236
What is meant by whole life costing?
Considering upfront and upfront costs of elements
237
Where have you considered maintenance and operational costs during design stages?
- High spec LED luminaires
- Maintenance- central heating plant instead of boilers has benefits of energy use and maintenance
- Maintenance - ASHP uses less energy and ducting
- Cleaning - roof access, cleaning facade methodology
238
What fire safety provisions are there in new buildings?
- Max occupancy numbers
- Fire evacuation plan, escape routes, signage, fire exits
- Extinguishers, alarms
- Sprinklers
- Fire dampers in ventilation ductwork
- Fire barriers - floor, wall and ceiling cavities
- Fire rated roller shutters
- Smoke control systems
239
Fire compartmentation? (in a building)
Passive fire protection- subdivides structure into fire compartments to limit spread of fire and smoke
240
What are automatic fire sprinklers, how are they activated?
- Sprinkler heads heat-activated
- Solder link melts / liquid-filled glass bulb shatters to activate and water directly released over head source
241
Different types of fire extinguisher and their typical uses?
- Water - wood, cardboard, textiles
- Foam - flammable liquids
- Dry powder - flammable liquids and electrical fires
- Carbon dioxide - electrical fires
- Wet chemical - cooking oil fires
242
How are fire barriers formed in suspended ceilings?
- Required in ceiling void if suspended ceiling not fire resistant
- Installed between soffit of floor above and suspended ceiling - ceiling void compartmented
- Need to consider if smoke stops are also required
243
What happens when services pass through fire barriers?
Need to be sealed to prevent fire spreading through service gap
244
What impact do new building regulations have on fire safety?
Buildings over 11m now need sprinklers
245
What impact will future building regs likely have?
- Prohibit combustible materials in external facade, i.e. timber decking and glass on balconies, insulation used
- Maybe high fire ratings required around ext facade
246
Design concerns for fire safety in tall buildings?
- Sprinklers (11m+)
- Dry riser
- Wet riser 50m+
- Fire fighting lifts
- No combustible materials in ext facade
- Fire walling in ceiling voids
- Dampers
247
How do you stop fire rising through buildings?
Compartmentation
248
What fire safety legislation has been introduced?
- Fire safety bill 2020 - updates the fire safety regulatory reform 2005
- Windows and doors part of ext walls, must be fire rated
- Building safety act came to force in January
249
What is section 278?
Developers enter into agreements with to make alterations to public highway
250
Types of bridge construction?
- Beam bridge with simple beam / cantilever
- Arch bridge
- Suspension bridge / cable stayed bridge
- Moveable bridge (swing bridge, draw bridge, lift bridge)
251
How does a cable stayed bridge work?
Load exerted from bridge deck and all live loads transferred through wires to towers and into ground anchorages
252
Difference between a tower and a pier?
- Towers protrude through deck vertically, provide connection point for cable stays - transfers load
- Piers support bridge deck
253
What systems can be introduced to a building to make it more sustainable?
- Biomass boilers
- Solar panels
- ASHP / GSHP
- LED lighting
- Insulation
- Onsite batteries for PV
- Car charging points
- BMS
254
Benefits / drawbacks of PV panels?
Advantages
- Can generate more than home use to sell energy back to grid
- Renewable energy source
- Reduced electricity bills
- Low maintenance costs
Disadvantages
- Cost
- Weather dependent
- Solar energy storage can be expensive
- Uses a lot of space
- Puncturing roof structure removes roof warranty
255
Best way to prive PV?
- Sqm rate from engineer
- Measured as nr in NRM, easier on sqm basis
256
Issues with biomass boilers?
- Primary source with gas backup - gas backup generally used instead
- Fuel pellet storage requires a lot of space, sourced from abroad
- Lots of maintenance
257
Drawbacks for wind turbines?
- Can be eye sores
- Potential to devalue property
- Requires specific windy conditions (between light and strong winds)
258
What is an EPC?
Energy Performance Certificate
A-G, A is best
259
Passivhaus house benefits and characteristics?
- Highly efficient building - increased costs by 5-8% but has significant energy consumption savings
- Less than 15kWh/MW space heating per hear
- Domestic applications don't consume more than 60kWh/m2
- Airtightness - no more than 0.6 air changes/hr
- Thermal comfort - indoor temps n.e. 25 ddegrees for 10% of hours
- Achieved by high insulation levels, air tight layer around facade, no thermal bridging, MVHR, triple glazed windows. Therefore less M&E plant
260
Legislation for clean air in cities?
UK clean air model 1997 - clean up city air by 2010 (still way behind)
261
Which product is more sustainable timber vs concrete?
- Depends on project- location, material source
- Generally timber, assuming from forestry steward council source
