Design and Specification Flashcards
What is Modern Methods of Construction
‘Modern Methods of Construction’ (MMC) is a wide term, embracing a range of offsite manufacturing and onsite techniques that provide alternatives to traditional house building.
What are some examples of Modern Methods of Construction
- Modular construction whereby three-dimensional units are produced in a factory
- Non-structural pods (typically fully-fitted kitchens or bathrooms) which are incorporated within load-bearing structures;
- Panelised systems which are transported to site as flat panel units.
- Sub-assemblies and components such as roof frames and floor cassette
What are some key peices of documentation relating to Modern Methods of Construction
2005 - The National Audit Office published ‘Using modern methods of construction to build homes more quickly and efficiently’
2017 - The National House Building Council (NHBC) launched an online MMC hub.
2018 - a forward-thinking solution to the UK housing crisis
What is the RICS report a forward-thinking solution to the UK housing crisis
The RICS has released a paper calling on government and the construction industry to embrace Modern Methods of Construction (MMC)
What are some Criticisms of Modern Methods of Construction
- Difficulty of defining the precise meaning of ‘modern methods of construction’
- A shift in risk - All risk will lie with one or two cotractors rather than a series of smaller contractors especially with modular units.
- The House of Lords Science & Technology Committee enquiry “undermine investment in British Manufactured masonry products that are preferred by consumers”
- Chemistry building at the University of Nottingham fire a fire occoured when the building was 70% complete. Gaps between the modular units were identified as being a factor as to why the fire was not contained
What is cross laminated timber
CLT is planed and kiln-dried to reduce moisture content, then stacked into layers at 90 degrees to the layer below, gluing the lamellas together. CLT has been in use since the mid-1990s. There are some variations of this including dowel laminated timber, panels and beams.
What are some advantages of CLT compared to steel or concrete
Lightweight - CLT is approximately 720kg/m3 whereas concrete is approximately 2400 kg,
Reduced carbon - Embodied Carbon +976 tonnes CLT , +2,000 tonnes Concrete of a CLT flat,
Larger spans - Used for sportcenters such as Richmond Olympic Oval and bridges such as Accoya Glulam Bridge at Sneek
What is a universal beam
A Universal Beam is primarily used a horizontal load bearer. The section is often taller than a Universal column.
What is a universal column
A column is designed to support a compressive load. The web section is similar or equal in width and height to the flange sections. The web is a bit thicker in a column. Meaning it can be used as a beam.
What is a Rolled steel Joist
Traditionally specified before BS 4-1:2005 Hot rolled rather than extruded. This can be identified by slightly slopped flanges due to manufacturing process.
What is Modular construction
‘Modular construction’ is a term used to describe the use of factory-produced pre-engineered building units that are delivered to site and assembled as large volumetric components or as substantial elements of a building
What are the benifits to Modular construction
Safer Construction - Eliminates most onsite hazards due to being mostly off site. The only significant hazard remaining is working at height.
Reduced Construction Schedule
Reduced Waste - When building in a factory, waste is eliminated by recycling materials, controlling inventory and protecting building materials
Improved Air Quality - completed in a factory-controlled setting using dry materials, the potential for high levels of moisture being trapped in the new construction is eliminated.
Imporved Qulaity Assurance - Achieved through repetition, inspection and operating in a factory-controlled environment
What are the disadvantages to Modular construction
Smaller Rooms - Due to the limatitions of transportations the room sizer are limited
Transportation Challenges - Difficulty transporting and handling modules due to their large weight and size can be costly and challenging within the confines of a small constructioin site.
No design changes - Due to the nature of modular construction alterations are near impossible and expensive.
What are the types of load on a building
Dead loads refer to the structure’s self weight and generally remain constant during the structure’s life.
Live loads, Live loads, also known as imposed loads, are usually temporary, changeable and dynamic. These include loads such as vehicle traffic, occupants, furniture and other equipment.
Enviromental loads
What are enviromental loads
Wind loads may not be a significant concern for small, massive, low-level buildings, but it gains importance with height, the use of lighter materials and the use of shapes that my affect the flow of air, typically roof forms.
Snow Loads are calculated by the projections made by snow at different parts of the structure, The amount of snow load depends on the height of building, size & shape of the roof, the location of building e.t.c
Earthquake Significant horizontal loads can be imposed on a structure during an earthquake. Buildings in areas of seismic activity need to be carefully analysed and designed to ensure they do not fail if an earthquake should occur.
Thermal loads All materials expand or contract with temperature change and this can exert significant loads on a structure. Expansion joints can be provided at points on long sections of structures such as walls and floors.
Ground movement such as heave and settelment can be design out by IS 1904 (1986): Code of practice for design and construction of foundations in soils.
How are loads catagorised
Concentrated loads (or point loads): Single loads that act over a relatively small area, such as column loads.
Line loads: Loads exert a load along a line, such as a partition’s weight on the floor.
Distributed (or surface) loads: These exert a load over a surface area, such as the weight of floors and roofing materials.
What are grades of OSB
OSB 1 - General purpose boards for furniture
OSB 2 - Load-bearing boards for dry use
OSB 3 - Load-bearing boards for wet use
OSB 4 - Heavy-duty load-bearing boards for wet use
What is OSB
An engineered wood-based panel consisting of three tiers of timber strands. (The outer 2 are orientated one way and the inner layer at 90 degrees to that)
What types of waterproofing systems are there
BS 8102:2009 indentifies three types;
- Type A - Barrier protection
- Type B - Structurally intergrated protection
- Type C - Drained protection
What are some considerations for concrete repair
Impact on surrounding area - sand blasting
Weather - wind, temperature, rain
Contamination - marine environment
Rienforcement protection - corrosion inhibitor
What are some considerations when specifying cavity barriers
Heat loss - meet part L
Water ingress - wind driven rain, surface grooves
Fire protection - 30 min fire barrier
Cavity width - cut on site for varying widths
Sustainablility - minor impact on SAP calculation
Zero maintenance
What are some considerations when specifying stair nosings
Profile - bull nose/rake/straight
Slip resistant - classification high/moderate/low
Floor covering - carpet/vinyl/ none
Colour - specified light reflectance value (contrasting)
What are some considerations when specifying roof lights
Use class - 3, fragile. 0, unrestricted access Sound reduction - double/triple glazing Thermal performance Slip resistance Testing method - hard body/soft body
What are some considerations when specifying EWI
Thermal performance - insulation thickness
Substrate - load bearing capacity, anchors, wind
Location - Marine enviroment, Galvinized mesh
Fire - Building height
Colour
How do you ensure Legislative compliance
Adhere to the following peices of legislation;
- The Town and Country Planning Acts
- Public health (BuildingRegulations)
- Construction (Design and Management) Regulations
- Control of Asbestos Regulations 2012
How would you check if a material is hazardous
Refer to the product data sheet. Failingthat contact the manufacturer directly.
What is RIBA Stage 0 Strategic definition
The client’s business case and strategic brief are assessed to ensure they have been properly considered’ and the scope of the project is defined.
What is RIBA Stage 1 Preparation and briefing
Involves developing the information that the design team will need to commence the design process at Stage 2. Broad specification is provided by the client such as;
- Space requirements
- Outline budget cost
- Quality asperations
- Time requirements
What is RIBA Stage 2
Outline specifications including; The design concept. Outline specifications. Schedules of accommodation. A planning strategy. The cost plan. Procurement options. Programme and phasing strategy. Buildability and construction logistics.
What is RIBA Stage 3 Spatial coordination
It suggests that a spatially coordinated design is a: ‘Design in which the client’s Spatial Requirements and the spaces required for any Building Systems;
- Plant and M&E space allocation
- Structural design
- Internal layout
What is RIBA Stage 4 Detailed design
Develop stage 3 without major spatial amendments including;
- Accoustic requirements
- Dimensions
- Fire requirements
- Aestetic requirements
- Thermal performance
- Corrosion resistance requirements
- Moisture resistance requirements
- Relevant standards
- Manufacturers and Products
- Workmanship standards
How do you produce specifications
We produce specifications using a software called NBS Chorus.
It allows you to select CAWS for example M60 finishes, K10 linings, C20 demolition.
It allows you to remove works sections that are not required by “parking them”.
It automatically includes extracts from British standards for example when specifying the finish of sandblasting metal the drop-down menu will let you select from Sa1, Sa2 and Sa3.
Chorus also has a directory of products and manufacturers.
The software also allows multiple users to edit a specification at one time, allowing for simple quality assurance.
What is an outline specification
An outline specification is a brief description of the main components to be used in construction. They should be described in sufficient detail to allow the cost consultant to prepare some approximate quantities. The components are broad such as;
- Cladding
- Substructure
- Flooring
- Roofing
- Ceilings
What is an Output-based specification
The output-based specification may be a development of the project brief, but it is separate from it as it defines only the outputs that are required from the project, it does not attempt to address how those outputs might be achieved.
What are some comon specification errors
- Referring to clause numbers on drawings can see that the contractor disregards various workmanship clauses.
- Specifying temporary works as this is the responsability of the contractor as temporary works coordinator
- Using the term ‘or similar approved’ in a specification. If you approve it you are assuming liability for it. Instead use the term ‘or acceptable equivalent’
- Name a very specific product and then provide performance characteristics for that product. It is not necessary and creates the potential for conflict resulting in claims.
- Always create a new specification for each project as standards, materials and best practice are consistently chaning.
What are perspective specifications
General requirements relating to regulations and standards.
The type of products and materials required.
The execution and installation methods required.
What are perfromance specifications
Performance specifications describe the result that is required from particular items and leave it to the contractor or supplier to satisfy that requirement. In effect it requires the contractor or supplier to complete the design.
What is the difference between perspective and performance specifications
Perspective - Specifies products and manufactures with workmanship and regulatory standard clauses
Performance - Requirements are specificed and the contractor puts fourth products that meet the requirements.
What is CAWS
Common Arrangement of Work Sections developed by the Construction Project Information Committee (CPIC), to address inconsistencies in specifications at the time. It works on a Letter and number system e.g.
A - Preliminaries
B - Complete buildings / structures / units
C - Demolition / Alteration /Renovation
D - Groundwork
NBS is beginning to move away from CAWS in favour of the Uniclass system.
What is Uniclass system
Uniclass is a voluntary classification system for the construction industry that can be used to organise information throughout all aspects of the design and construction process and designed to be BIM level 2 compatible. It works on a XX-00-00-00 system to identify not only specification items but drawings, reports and cost informaiton.
How would you size a room
In accordance with Technical housing standards - nationally described space standard
What are some changes to the 2020 Plan of Work
The green overlay has been adopted into the main plan.
Stage 2 Preparation and brief were changed to Preparation and briefing to demonstrate that the brief is an ever-evolving document.
Stage 3 changed developed design to spatial design. To show it’s not changing the concept but coordinating the spaces.
the 2013 guide was unclear when planning permission should be submitted 2-4 the 2020 plan clearly states at the end of stage 3.
Stage 5 changed to manufacturing and construction from construction as I now recognise modern methods of construction such as offsite manufacturing and offsite construction.
What are the plan of work stages
Stage 0 - Strategic definition Stage 1 - Preparation and briefing Stage 2 - Concept design Stage 3 - Spatial coordination Stage 4 - Technical design Stage 5 - Manufacturing and construction Stage 6 - Handover Stage 7 - Use
what is a u-value
Thermal transmittance, also known as U-value, is the rate of transfer of heat through a structure, divided by the difference in temperature across that structure.
What does the number after FD on a fire door represent
The minimum level of resistance to smoke/fire for a specified number of minutes. Typically 30, 60, 90, 120.
What is the Technical housing standards - nationally described space standard
The document sets out the minimum Gross Internal Areas for new dwellings. It takes into account Number of stories, number of bedrooms, built-in storage and number of bed spaces.
What is BS EN 1504
BS EN 1504 - Products and systems for the repair and protection of concrete structures
What are BS EN 1504-9 10 “principles” for the repair and protection of concrete structures
- Protection against ingress
- Moisture control
- Concrete restoration
4-5. Structural strengthening - Resistance to chemicals
- Preservation or restoring passivity
- Increasing resistivity
- Cathodic control
- Cathodic protection.
