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NSSCO Building Studies 6186 practice questions

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Question 1Health, Safety and Site Practice

On a Namibian building site, which item of personal protective equipment is specifically required when workers are exposed to the noise of a concrete poker or angle grinder?

  1. A hard hat
  2. A high-visibility vest
  3. Ear protection such as earplugs or earmuffs Correct answer.
  4. Steel-toe safety boots

Explanation

Hearing damage from sustained high noise levels is irreversible, so earplugs or earmuffs must be worn when noise exposure is high. The other items protect against impact, visibility and foot injury rather than sound.

Question 2Health, Safety and Site Practice

A scaffold is being erected next to a public footpath in a town. Which control best protects pedestrians from falling materials?

  1. Erecting a fan or debris netting and a covered walkway over the path Correct answer.
  2. Asking pedestrians to look up while passing the site
  3. Placing a single warning cone at the site entrance
  4. Restricting scaffold work to early morning hours

Explanation

Falling-object risk to the public is controlled by physical containment such as debris netting, fans and a protected walkway. Warnings and timing alone do not stop a dropped object from striking someone.

Question 3Health, Safety and Site Practice

Which statement correctly describes the purpose of a site induction?

  1. It certifies that a worker is competent in every trade on site
  2. It replaces the need for task-specific training on plant and equipment
  3. It familiarises new workers with site hazards, rules and emergency arrangements before they start work Correct answer.
  4. It is a record of wages and hours worked on site

Explanation

A site induction introduces the specific hazards, site rules, welfare arrangements and emergency procedures of that particular site. It does not replace trade training, competence assessment or payroll records.

Question 4Health, Safety and Site Practice

A worker must enter a deep excavation to inspect a pipe joint. Which precaution is essential before entry?

  1. The excavator should remain running nearby for lighting
  2. The worker should descend quickly to minimise time at the surface
  3. A competent person must inspect the excavation and confirm supports, access and safe atmosphere Correct answer.
  4. A colleague should stand on the spoil heap to watch

Explanation

Excavations can collapse or contain hazardous atmospheres, so a competent person must inspect and confirm support, safe access and air quality before anyone enters. Quick entry, spoil-heap watchers and idling plant add risk rather than control it.

Question 5Health, Safety and Site Practice

What is the main reason for keeping gangways and stairways on a construction site clear of materials?

  1. To provide a safe means of escape and prevent slips and trips Correct answer.
  2. To reduce the amount of material ordered
  3. To allow the crane to operate faster
  4. To make the site look tidy for the client's visit

Explanation

Clear routes allow workers to move safely and to escape quickly in an emergency, and they reduce slip and trip injuries. Tidiness, ordering and crane speed are not the primary safety reason.

Question 6Health, Safety and Site Practice

A compressed gas cylinder is delivered to site. Which storage arrangement meets basic site safety requirements?

  1. Stored upright and secured in a ventilated area away from ignition sources, with valve caps fitted Correct answer.
  2. Stacked horizontally under a tarpaulin against a wall
  3. Left upright but unsecured next to the site generator
  4. Laid flat in a locked site office beside the heater

Explanation

Cylinders should be kept upright and restrained so they cannot fall, in a ventilated place away from heat and ignition, with protective caps on. Laying them down, hiding them under covers or placing them near a generator increases the risk of leaks and fire.

Question 7Health, Safety and Site Practice

Which document should be prepared before a task such as working at height on a roof edge, setting out the sequence, hazards and controls?

  1. A delivery note
  2. A site diary entry
  3. A method statement Correct answer.
  4. A materials requisition

Explanation

A method statement describes how a task will be carried out safely, including the sequence of work, hazards and control measures. Delivery notes, diaries and requisitions record logistics rather than planned safety controls.

Question 8Health, Safety and Site Practice

A worker is about to use a mobile tower scaffold that has no guardrails fitted on the top platform. What is the correct action?

  1. Use it only for short jobs of under ten minutes
  2. Ask a colleague to hold the tower steady while working
  3. Do not use it until guardrails and toe boards are fitted and the tower is checked Correct answer.
  4. Tie a rope around the platform as a substitute for guardrails

Explanation

A tower without guardrails exposes workers to falls, so it must not be used until it is properly completed and inspected. Short duration, improvised ropes and a colleague holding the tower do not provide fall protection.

Question 9Health, Safety and Site Practice

What does the term 'welfare facilities' cover on a construction site?

  1. Drinking water, toilets, washing facilities and shelter for rest and meals Correct answer.
  2. The site office furniture and stationery
  3. The storage yard for cement and timber
  4. The plant and machinery used for earthworks

Explanation

Welfare facilities are the basic provisions that protect workers' health and dignity, namely drinking water, sanitary conveniences, washing facilities and a place to rest and eat. Office furniture, storage and plant are not welfare provisions.

Question 10Health, Safety and Site Practice

Cement dust is being generated while mixing mortar in a confined area. Which combination of controls is most appropriate?

  1. Working faster to finish before dust builds up
  2. Opening a door and continuing without any protection
  3. Damping down or using a mixer with dust extraction, plus suitable respiratory protection Correct answer.
  4. Wearing safety goggles only

Explanation

Cement dust is a respiratory hazard, so suppression or extraction at source should be combined with appropriate respiratory protection. Goggles protect the eyes only, and ventilation alone or speed of work does not control the dust inhaled.

Question 11Health, Safety and Site Practice

Which action best describes the safe use of a ladder for short-duration access?

  1. Lean it against a fragile gutter without tying it
  2. Stand on the top two rungs to reach higher
  3. Set it on firm level ground at about a 75-degree angle and secure the top Correct answer.
  4. Use it as a horizontal platform between two supports

Explanation

A ladder should stand on firm, level footing at roughly a one-in-four angle and be secured to prevent slipping. Leaning on fragile surfaces, standing on the top rungs and using a ladder horizontally are all unsafe practices.

Question 12Health, Safety and Site Practice

A worker suffers a minor cut from a sharp edge on site. What is the first priority in the site first-aid arrangements?

  1. Send the worker home without treatment
  2. Ask the client to decide whether treatment is needed
  3. Continue work and report it at the end of the month
  4. Treat the injury promptly and record it in the accident book Correct answer.

Explanation

First-aid arrangements should ensure prompt treatment and a written record of the injury. Delaying treatment, sending the worker away untreated or deferring the decision to the client fails to meet basic first-aid duties.

Question 13Health, Safety and Site Practice

Which of the following best explains why a permit-to-work system is used for hot work such as welding in a basement?

  1. It allows welding to proceed without any supervision
  2. It formally confirms that fire precautions and isolation are in place before work starts Correct answer.
  3. It replaces the need for a fire extinguisher at the work location
  4. It transfers legal responsibility to the welder alone

Explanation

A permit-to-work is a formal check that specified precautions, such as removing combustibles, fire watch and isolation, are in place before high-risk work begins. It does not remove the need for firefighting equipment, supervision or shared responsibility.

Question 14Health, Safety and Site Practice

A crane is lifting a precast concrete panel over a site access road. Which control is most important for people below?

  1. Excluding people from the area beneath the load and using a planned lifting route Correct answer.
  2. Relying on the crane operator to shout a warning
  3. Allowing workers to walk beneath the load if they hurry
  4. Permitting the lift only when the wind is strong

Explanation

The area under a suspended load is a danger zone, so people must be excluded and the lift planned to avoid travel over occupied areas. Shouting, hurrying beneath a load or lifting in strong wind does not control the risk.

Question 15Health, Safety and Site Practice

What is the primary purpose of a site-specific risk assessment?

  1. To identify hazards, evaluate the risk and record suitable control measures for that site's activities Correct answer.
  2. To list the names of all workers on the payroll
  3. To record the weather conditions each day
  4. To calculate the quantity of bricks required

Explanation

A risk assessment identifies hazards arising from the work, judges how severe and likely the harm is, and records the controls needed to reduce risk. Payroll, material quantities and weather logs are separate records.

Question 16Health, Safety and Site Practice

A worker reports dizziness and headache after entering a newly painted, poorly ventilated basement store. What is the most appropriate immediate response?

  1. Tell the worker to continue but take more frequent breaks
  2. Give the worker a hot drink and let them rest inside the store
  3. Seal the basement and ignore the complaint
  4. Evacuate the space, ventilate it and keep people out until the atmosphere is confirmed safe Correct answer.

Explanation

Dizziness and headache suggest exposure to solvent vapour or oxygen deficiency, so the space should be evacuated, ventilated and only re-entered once the atmosphere is proven safe. Resting inside, continuing work or ignoring the report leaves others exposed.

Question 17Health, Safety and Site Practice

Which of these is a recognised safe practice when manually handling heavy blocks on site?

  1. Carrying the load at arm's length for balance
  2. Breaking the load into smaller loads and keeping it close to the body with a straight back Correct answer.
  3. Twisting the trunk while lifting to save time
  4. Lifting with straight legs and a bent back

Explanation

Reducing the load size and keeping it close to the body with a straight back lowers the strain on the spine. Twisting, bending the back or holding loads at arm's length greatly increases the risk of back injury.

Question 18Health, Safety and Site Practice

A site has several subcontractors working in the same area. Who is responsible for coordinating health and safety between them?

  1. The client's architect alone
  2. The materials supplier delivering to site
  3. The principal contractor or main contractor controlling the site Correct answer.
  4. Each subcontractor working independently without liaison

Explanation

The contractor in control of the site must coordinate the activities of all those working there so that risks created by one trade are communicated to others. Independent working without liaison, suppliers and the architect do not hold that coordinating duty.

Question 19Health, Safety and Site Practice

What is the main hazard associated with using a cartridge-operated fixing tool on a concrete slab?

  1. The tool cannot be used on concrete
  2. The cartridges are harmless and need no storage controls
  3. The tool produces excessive noise only
  4. The fastener or fragments can fly off and strike people nearby Correct answer.

Explanation

Cartridge fixing tools drive fasteners at high velocity, so a ricochet or fragment can injure the operator or bystanders. Noise is not the only hazard, the tool is designed for concrete, and cartridges are explosive items requiring controlled storage.

Question 20Health, Safety and Site Practice

Which practice is correct for the safe storage of flammable liquids such as paint thinners on site?

  1. Pour surplus thinner onto the ground away from buildings
  2. Keep them in a labelled, fire-resistant store with bunding away from ignition sources Correct answer.
  3. Store them in open buckets near the site canteen
  4. Keep them in the cab of a delivery vehicle overnight

Explanation

Flammable liquids should be kept in a designated fire-resistant store with spill containment and clear labelling, away from heat and ignition. Open buckets, ground disposal and vehicle cabs all create fire and pollution risks.

Question 21Health, Safety and Site Practice

What does a 'toolbox talk' aim to achieve on a construction site?

  1. A negotiation of wage rates with the workforce
  2. A handover of tools between shifts
  3. A formal disciplinary hearing for unsafe workers
  4. A short briefing on a specific hazard or task to reinforce safe working practices Correct answer.

Explanation

A toolbox talk is a brief, focused briefing that reminds workers of a particular hazard and the controls for it. It is not a disciplinary process, a pay negotiation or a tool handover.

Question 22Health, Safety and Site Practice

A worker notices that a guard has been removed from a bench saw. Which action best reflects a positive safety culture?

  1. Stop using the machine, report the defect and ensure it is isolated until repaired Correct answer.
  2. Use the saw only for small pieces of timber
  3. Ask another worker to use the saw instead
  4. Continue using the saw carefully without the guard

Explanation

Removing a machine from service and reporting the defect prevents injury and shows that workers feel able to raise concerns. Continuing, passing the task to someone else or restricting the size of timber still exposes users to an unguarded blade.

Question 23Health, Safety and Site Practice

Which statement correctly explains the purpose of an exclusion zone around an area where piling is taking place?

  1. To reserve parking space for the piling contractor
  2. To keep unauthorised people out of an area where plant, noise and falling objects present serious risks Correct answer.
  3. To mark where materials should be stacked
  4. To show the boundary of the client's property

Explanation

An exclusion zone physically keeps people away from high-risk operations such as piling, where heavy plant, noise and falling objects can cause serious harm. Parking, material stacking and property boundaries are unrelated purposes.

Question 24Health, Safety and Site Practice

During a site inspection, a supervisor finds an unsecured edge on the second-floor slab with a two-metre drop. Which control should be given priority?

  1. Rely on the workers' experience to avoid falls
  2. Install suitable edge protection such as guardrails and toe boards before work continues Correct answer.
  3. Place a warning sign at the edge and continue working
  4. Ask workers to stay at least one metre from the edge

Explanation

Where a fall from height is possible, collective protection such as guardrails and toe boards should be installed as the priority control. Signs, distance rules and experience do not physically prevent a fall.

Question 25Building Drawing, Plans and Specifications

In a set of building drawings, which sheet typically shows the overall layout of the site, the position of the building and the main levels?

  1. The window elevation sheet
  2. The structural detail sheet
  3. The door schedule
  4. The site plan Correct answer.

Explanation

The site plan establishes the relationship between the building and its plot, showing boundaries, access, orientation and principal ground levels. Schedules and detail sheets describe components rather than overall layout, so they cannot serve this purpose.

Question 26Building Drawing, Plans and Specifications

A drawing is labelled at a scale of 1:50. What does one millimetre measured on the drawing represent on the actual building?

  1. 1 millimetre
  2. 50 millimetres Correct answer.
  3. 500 millimetres
  4. 5 millimetres

Explanation

A ratio scale of 1:50 means one unit on the drawing equals fifty of the same units in reality. Therefore 1 mm scales up to 50 mm on site, and a 100 mm wall would be drawn 2 mm thick.

Question 27Building Drawing, Plans and Specifications

Which line type is conventionally used on a building drawing to indicate a feature that is hidden above the cut plane, such as a wall over a beam?

  1. A dashed line Correct answer.
  2. A wavy freehand line
  3. A continuous thick line
  4. A chain dotted line

Explanation

Dashed lines represent edges or surfaces that exist but are not visible in the view, such as overhead features or concealed construction. Continuous thick lines show visible outlines, so they cannot denote hidden work.

Question 28Building Drawing, Plans and Specifications

On a floor plan, a door is drawn with a quarter-circle arc. What does the arc represent?

  1. The fall of the floor towards a drain
  2. The position of the lintel above
  3. The direction and sweep of the door leaf as it opens Correct answer.
  4. The thickness of the door frame

Explanation

The arc is a standard convention showing the swing of the door leaf and the side on which it is hinged. It allows a reader to check that doors do not clash and that they open in a sensible direction.

Question 29Building Drawing, Plans and Specifications

What is the main purpose of a building specification?

  1. To replace the need for any drawing on site
  2. To show the exact position of every reinforcement bar
  3. To describe the quality of materials and workmanship required for the works Correct answer.
  4. To record the contractor's daily labour returns

Explanation

The specification is the written document that sets out materials, standards and workmanship that drawings cannot convey graphically. Drawings and specification are complementary and are read together as part of the contract documents.

Question 30Building Drawing, Plans and Specifications

A drawing title block carries the project name, drawing number and revision letter. Why is the revision letter important on a construction project?

  1. It records the name of the draughtsperson's supervisor
  2. It shows the grade of paper used for printing
  3. It indicates the scale at which the drawing must be read
  4. It identifies which issue of the drawing is current and supersedes earlier copies Correct answer.

Explanation

Revision control ensures that everyone on site works from the latest information and that superseded drawings are withdrawn. Without it, contractors could build to outdated details and cause costly rework.

Question 31Building Drawing, Plans and Specifications

Which document is prepared to accompany a tender and lists the individual items of work with quantities so that contractors can price them consistently?

  1. The as-built drawing set
  2. The bill of quantities Correct answer.
  3. The site diary
  4. The building permit application

Explanation

A bill of quantities itemises work with measured quantities, giving all tenderers a common basis for pricing. It also supports valuation of variations and interim payments once construction begins.

Question 32Building Drawing, Plans and Specifications

A plan is drawn at 1:100 and a wall measures 60 mm on the drawing. What is its actual length?

  1. 0.6 m
  2. 6.0 m Correct answer.
  3. 600 mm
  4. 60 m

Explanation

At 1:100 each drawing millimetre represents 100 mm, so 60 mm on paper equals 6000 mm, which is 6.0 m. Multiplying by the scale factor and converting millimetres to metres gives the site dimension.

Question 33Building Drawing, Plans and Specifications

On a section drawing, what does the term 'cut plane' refer to?

  1. The finished floor level of the ground storey
  2. The imaginary vertical plane through the building at which the section is taken Correct answer.
  3. The top edge of the roof covering
  4. The boundary line of the site

Explanation

A section is produced by imagining the building sliced by a vertical plane and viewing the cut face. Everything beyond the plane is drawn in elevation, while the cut surfaces are shown hatched or poché.

Question 34Building Drawing, Plans and Specifications

In architectural drawing convention, what does hatching a wall on a floor plan usually indicate?

  1. That the wall is to be demolished
  2. That the wall is cut by the horizontal section plane Correct answer.
  3. That the wall is below ground level
  4. That the wall is made of timber only

Explanation

A floor plan is a horizontal section taken about one metre above floor level, so walls crossed by that plane are shown cut and are hatched or filled. The hatch pattern may also hint at the material, but the primary meaning is that the element is cut.

Question 35Building Drawing, Plans and Specifications

A drawing carries the note 'FFL +0.450'. What does this tell the reader?

  1. The finished floor level is 450 mm above the datum Correct answer.
  2. The foundation is 450 mm deep
  3. The ceiling height is 450 mm
  4. The floor falls 450 mm towards the drain

Explanation

Levels are given relative to a project datum, usually taken as 0.000 at ground floor. A note of +0.450 therefore means that floor surface sits 450 mm above that datum.

Question 36Building Drawing, Plans and Specifications

Why are grid lines lettered and numbered on a structural or architectural drawing?

  1. To number the drawing sheets in the set
  2. To show the order in which rooms were designed
  3. To indicate the sequence of construction stages
  4. To provide a reference system for locating columns and walls Correct answer.

Explanation

A grid of numbered and lettered axes allows any column, wall or footing to be located precisely by reference, for example 'column at grid C4'. This avoids ambiguity when dimensions are read on site or in schedules.

Question 37Building Drawing, Plans and Specifications

Which statement best describes the difference between a location drawing and a detail drawing?

  1. A location drawing is drawn to scale, while a detail drawing never carries a scale
  2. A location drawing is prepared by the contractor, while a detail drawing is prepared by the client
  3. A location drawing shows where work is situated, while a detail drawing enlarges how it is constructed Correct answer.
  4. A location drawing is issued after completion, while a detail drawing is issued at tender

Explanation

Location drawings such as plans, sections and elevations place the works in context, whereas detail drawings enlarge junctions and components to explain assembly. Both are usually drawn to a stated scale and are produced by the designer.

Question 38Building Drawing, Plans and Specifications

A door schedule lists a door type as 'D3, 900 x 2100, FD30'. What does FD30 indicate?

  1. A door with a 30 mm thick leaf
  2. A door supplied in 30 days
  3. A door with a 30 dB acoustic rating
  4. A fire door giving 30 minutes of fire resistance Correct answer.

Explanation

The FD prefix with a number of minutes is the standard designation for a fire-resisting door set, so FD30 means thirty minutes' resistance. The schedule then ties this performance requirement to a specific door type and size.

Question 39Building Drawing, Plans and Specifications

What is the role of a setting-out plan on a building project?

  1. It fixes the exact position and dimensions of the building and its principal elements on the ground Correct answer.
  2. It lists the specification clauses for finishes
  3. It records the contractor's plant and equipment on site
  4. It shows the temporary site offices and stores

Explanation

A setting-out plan translates the design into dimensions and references that the site team can use to peg out the building accurately. It typically works from a grid and a known datum so that positions can be checked.

Question 40Building Drawing, Plans and Specifications

A plan shows a staircase with an arrow labelled 'UP' and a break line across the flight. Why is the break line used?

  1. To show where the stair changes material
  2. To mark the position of the handrail fixing
  3. To indicate that the stair is unsafe and must be removed
  4. To avoid drawing the whole flight and to show the stair continues beyond the cut Correct answer.

Explanation

A break line allows the draughtsman to show only the lower part of a flight on the floor plan, since the upper part would be cut away by the section plane. The arrow confirms the direction of ascent from that floor.

Question 41Building Drawing, Plans and Specifications

Which of these is the correct order of precedence when a discrepancy is found between contract documents, in the absence of a stated hierarchy?

  1. Drawings, then bill of quantities, then specification
  2. All documents rank equally and the contractor chooses
  3. Specification, then drawings, then bill of quantities Correct answer.
  4. Bill of quantities, then specification, then drawings

Explanation

Where no hierarchy is stated, the specification normally governs quality and the drawings govern quantity and position, with the bill of quantities ranking after both. A well-drafted contract states the order explicitly to avoid disputes.

Question 42Building Drawing, Plans and Specifications

A drawing is marked 'NTS'. What does this abbreviation mean and what is its consequence for measuring from the drawing?

  1. No timber supplied, so the detail is incomplete
  2. North to south, so orientation must be reversed
  3. Newly transferred sheet, so the drawing is provisional
  4. Not to scale, so dimensions must be read from written figures rather than scaled Correct answer.

Explanation

'Not to scale' warns that the drawing may have been distorted or is schematic, so scaling off it would give wrong dimensions. The written dimensions and the schedule take precedence over any measurement taken from the paper.

Question 43Building Drawing, Plans and Specifications

On a site plan, a north point is shown rotated relative to the sheet edge. Why is this important for the designer?

  1. It fixes the position of the site boundary fence
  2. It determines the drawing scale to be used
  3. It allows solar gain, prevailing wind and daylight to be assessed for each elevation Correct answer.
  4. It sets the finished floor level of the building

Explanation

Orientation governs how the sun and prevailing winds strike each facade, which affects overheating, shading and natural lighting. The rotated north point lets the reader relate the drawn layout to true bearings.

Question 44Building Drawing, Plans and Specifications

A reinforced concrete beam is detailed with the note '3T20'. In a bar schedule using this notation, what does it mean?

  1. Three stirrups at 200 mm spacing
  2. Three high-yield bars of 20 mm diameter Correct answer.
  3. Twenty bars of 3 mm diameter
  4. Three bars at 20 mm centres

Explanation

The number gives the count of bars and the figure after the letter gives the bar diameter in millimetres, with T denoting high-yield steel. So 3T20 is three 20 mm diameter bars, which the bar schedule then locates.

Question 45Building Drawing, Plans and Specifications

A drawing shows a dimension of 2400 mm between grid lines, but the scaled measurement on a 1:50 print gives 2450 mm. Which value should govern, and why?

  1. 2400 mm, because written dimensions take precedence over scaled measurements Correct answer.
  2. Either value, since the difference is within tolerance
  3. The average of the two values
  4. 2450 mm, because the print is the most recent information

Explanation

Written dimensions are the authoritative statement of size, and paper may stretch or shrink during printing. Scaled measurements are indicative only and must never override a stated dimension.

Question 46Building Drawing, Plans and Specifications

A section through a pitched roof shows a chain-dotted vertical line from ridge to eaves with the note 'RL 6.200'. What does RL denote?

  1. Roof load, the imposed load on the truss
  2. Reduced level, the height of that point relative to the datum Correct answer.
  3. Render line, the finish to the gable
  4. Ridge length, the span of the roof

Explanation

RL stands for reduced level, the surveyed height of a point expressed relative to an agreed datum. On a section it fixes the ridge height so that the roof geometry can be set out on site.

Question 47Building Drawing, Plans and Specifications

A detail drawing of a wall-floor junction is drawn at 1:5 and shows a 50 mm insulation board. How thick should the board appear on the drawing?

  1. 5 mm
  2. 10 mm Correct answer.
  3. 50 mm
  4. 250 mm

Explanation

At 1:5 the drawing is one fifth of full size, so a 50 mm board is drawn as 50 divided by 5, which is 10 mm. Dividing the real dimension by the scale denominator gives the drawn size.

Question 48Building Drawing, Plans and Specifications

A drawing issue sheet records revision B as 'issued for construction' and revision C as 'issued for tender'. Which revision should the site team build from, and why?

  1. Neither, until a revision D is issued
  2. Revision C, because tender issues always follow construction issues
  3. Revision B, because construction issues supersede earlier tender information Correct answer.
  4. Both revisions, since they describe the same design

Explanation

The status of an issue determines its use: tender information is for pricing, while construction issues authorise building. If revision B is the construction issue, it is the controlling document for the works.

Question 49Setting Out and Site Preparation

Before any setting out begins on a greenfield site, which survey task must normally be completed first to establish a fixed reference for all later measurements?

  1. Erecting the profile boards around the building line
  2. Excavating the foundation trenches to formation level
  3. Marking the centre lines of internal partition walls
  4. Establishing a site datum from an Ordnance Survey benchmark Correct answer.

Explanation

All setting out depends on a fixed, known level or position that other measurements can be referred back to, so a datum is transferred from a reliable benchmark before any physical work starts. Trench excavation and profile erection are later stages that themselves rely on that reference.

Question 50Setting Out and Site Preparation

A rectangular building is to be set out using the 3-4-5 method. The first corner peg and the line of the long side are already fixed. What is the purpose of measuring 3 m along one line, 4 m along the other and adjusting until the diagonal reads 5 m?

  1. To locate the position of the nearest site boundary
  2. To check that the two sides are equal in length
  3. To establish the reduced level of the corner peg
  4. To confirm the two lines meet at exactly 90 degrees Correct answer.

Explanation

A triangle with sides in the ratio 3:4:5 is right-angled, so when the diagonal across the two measured legs equals 5 m the included angle between them is 90 degrees. The method checks squareness only and says nothing about levels or boundary positions.