Red Seal Practice
Chapter VI

Demountable Partitions and Access Flooring

Red Seal Practice study guide with diagrams.

Demountable Partitions and Raised Access Floors

Chapter Introduction

Demountable partitions and raised access floors are two distinct interior finishing systems that are often combined in modern commercial and institutional buildings. For the Red Seal exam, you must master not only installation techniques, but also applicable Canadian standards, dimensional tolerances, load calculations, and work sequences. This chapter covers all the knowledge required to succeed on questions related to these systems.

Demountable Partitions

Definition and Classification

A demountable partition is a non-load-bearing interior separation system designed to be installed, relocated, and reinstalled without destruction of components. Unlike permanent partitions made of metal studs and gypsum board, demountable partitions are factory-manufactured and assembled on site using a modular system.

There are three main categories:

TypeCharacteristicsTypical Use
**Solid partitions**Solid panels in steel, aluminum, or glassPrivate offices, conference rooms
**Glazed partitions**Panels with frames and glass infillOpen offices, meeting rooms
**Mixed partitions**Combination of solid and glazed panelsFlexible layouts

Main Components

A demountable partition system includes:

Base plates (or base shoes): profiles fixed to the floor
Vertical studs: profiles in galvanized steel or extruded aluminum
Horizontal rails: profiles connecting the studs
Infill panels: sheet steel, tempered glass, fire-retardant MDF
Connection joints: H, T, or L-shaped profiles depending on the configuration
Accessories: integrated doors, cable pass-throughs, ventilation grilles

Tolerances and Adjustments

The floor must have a flatness of ± 3 mm over 3 meters for installation without excessive shimming. If the slab exceeds this tolerance, you must use leveling shims made of steel or plastic, never wood.

The plumbness of studs must be checked with a laser level or plumb bob. The maximum tolerance is 1.5 mm per meter of height.

Installation Procedure

22.Take measurements: measure the length, height, and width of each bay
23.Floor layout: snap reference lines using a chalk line
24.Install base plates: anchor to the floor with expansion anchors or concrete screws, spaced at maximum 600 mm
25.Install studs: engage studs into base plates, check plumbness
26.Install panels: insert panels into profiles, starting from the bottom
27.Install rails: lock rails to studs according to manufacturer specifications
28.Final adjustment: check alignment, flatness, and door operation

Quantity Calculations

To calculate the number of studs required:

Number of studs = (Total partition length ÷ Stud spacing) + 1

Example: 6-meter partition with studs spaced at 1.2 m

N = (6 ÷ 1.2) + 1 = 6 studs

For panels, account for waste of 5 to 10% depending on layout complexity.

Raised Access Floors

Definition and Components

A raised access floor (or technical floor) is a floor system elevated above the concrete slab, creating a void space for routing electrical cables, data cables, and ventilation ducts. It consists of:

Adjustable pedestals (or supports): steel, with a base plate and threaded rod
Stringers: metal profiles connecting the pedestals
Floor panels: tiles measuring 600 mm × 600 mm or 610 mm × 610 mm
Accessories: access plates, ventilation grilles, ramps, stairs

Types of Systems

SystemFree HeightLoad CapacityUse
**Low height**50 to 150 mm5 to 8 kN/m²Renovation, minimal cabling
**Medium height**150 to 300 mm8 to 12 kN/m²Offices, computer rooms
**High height**300 to 600 mm12 to 20 kN/m²Data centers, server rooms

Loads and Calculations

Concentrated load is the maximum load applied over a small area (typically 25 mm × 25 mm). Uniformly distributed load is the load evenly distributed over the entire panel surface.

To calculate the total load on one pedestal:

Load per pedestal = (Uniform load × Panel area) ÷ Number of pedestals supporting the panel

Example: 600 mm × 600 mm panel (0.36 m²), uniform load of 10 kN/m², panel supported by 4 pedestals:

Load per pedestal = (10 × 0.36) ÷ 4 = 0.9 kN

Performance Standards

Raised access floors must comply with the requirements of CSA Z-101 (Canadian standard for raised access floors). Panels must support a minimum concentrated load of 3 kN with a maximum deflection of 2.5 mm.

Installation Procedure

54.Prepare the slab: complete cleaning, apply primer if necessary
55.Layout: snap reference lines from the center of the room
56.Install pedestals: secure base plates with epoxy adhesive or anchors, adjust height using the threaded rod
57.Install stringers: clip stringers onto pedestal heads
58.Check level: use a rotating laser level, adjust each pedestal individually
59.Install panels: place panels onto stringers, starting from the corner farthest from the door
60.Final adjustment: check overall level, stability, and joint alignment

Alignment and Leveling

The flatness of the finished floor must be ± 1.5 mm over 3 meters. Leveling is done using a precision rotating laser level. Each pedestal is adjusted individually by rotating the threaded rod.

Pedestal height formula:

Pedestal height = Desired free height − Panel thickness − Stringer height

System Integration

Coordination with Other Trades

Demountable partitions and raised access floors must be coordinated with:

Electrical: cable routing in the raised floor, outlet boxes in partitions
HVAC: ventilation grilles integrated into panels, diffusers in partitions
Plumbing: passages for conduits, floor drains
Fire protection: smoke detectors, sprinklers, fire stops

Fire Stopping and Permeability

Demountable partitions must comply with the requirements of the National Building Code of Canada (NBC) regarding fire propagation. Cable and conduit penetrations must be sealed with ULC-certified fire-stop products (Underwriters Laboratories of Canada).

Expansion joints must be provided every 12 meters in demountable partitions to allow for thermal expansion.

Universal Accessibility

According to the NBC, doors integrated into demountable partitions must have a minimum clear width of 850 mm. Thresholds must not exceed 13 mm in height. Handles must be installed at a height of 900 to 1000 mm from the finished floor.

Applicable Standards and Codes

National Building Code of Canada (NBC)

The NBC applies to demountable partitions and raised access floors in the following sections:

Section 3.1: General construction requirements
Section 3.2: Fire safety
Section 3.3: Occupant safety
Section 3.4: Exits
Section 3.8: Accessibility

Canadian Electrical Code, Part I

The Canadian Electrical Code, Part I (C22.1-21) applies to electrical installations in raised access floors:

Rule 12-200: Wiring in raised access floors — cables must be supported at maximum intervals of 1.5 m
Rule 12-202: Outlet boxes in raised access floors must be accessible
Rule 12-204: Cables must be protected against mechanical damage

CSA B149.1 — Natural Gas and Propane Code

Although less common, CSA B149.1 applies if gas lines pass through raised access floors. Pipes must be installed with a minimum clearance of 50 mm from floor components.

Other Relevant Standards

CAN/ULC-S102: Flame spread and smoke test
CAN/ULC-S114: Fire resistance test
ASTM E84: Surface burning characteristics

Calculations and Conversions

Unit Conversions

ImperialMetric
1 foot0.3048 m
1 inch25.4 mm
1 pound0.4536 kg
1 psi6.895 kPa
1 foot-pound1.356 N·m

Calculating Panel Area

Panel area = Length × Width

For a 600 mm × 600 mm panel:

A = 0.6 × 0.6 = 0.36 m²

Number of Panels Required

Number of panels = Total room area ÷ Area of one panel

Add 5% for cuts and waste. For a 24 m² room:

N = 24 ÷ 0.36 = 66.67 → 67 panels

With waste: 67 × 1.05 = 70.35 → 71 panels

Calculating Linear Load on a Partition

Linear load = Panel weight × Partition height

For a 3 m high partition with panels weighing 25 kg/m²:

Load = 25 × 3 = 75 kg/m

Quality Control Procedures

Pre-Installation Checks

Verify that the concrete slab is dry (moisture below 4% using a moisture meter)
Confirm that site dimensions match the drawings
Inspect materials for transport damage
Verify that material certificates of compliance are available

Checks During Installation

Check stud plumbness with a 2 m level
Check panel joint alignment with a 1 m straightedge
Test the operation of integrated doors
Check the raised floor level with a laser level

Final Checks

Perform a load test on a sample of panels
Verify continuity of grounding on metal components
Confirm that all cable pass-throughs are sealed with fire-stop materials
Document deviations and corrections made

Workplace Safety

Specific Hazards

Falls: working at height when installing partitions
Cuts: handling metal panels and glass
Heavy loads: lifting floor panels (15 to 25 kg each)
Dust: cutting gypsum and MDF panels

Personal Protective Equipment (PPE)

Safety helmet with chin strap
Safety glasses with side shields
Protective gloves (leather for handling glass)
Safety footwear with steel toe
N95 respirator when cutting

Lifting Rules

Maximum recommended load for manual lifting: 23 kg according to CCOHS (Canadian Centre for Occupational Health and Safety) guidelines. For heavier loads, use a forklift or a vacuum lifting device.

Pitfalls to Avoid

149.Confusing tolerances: the flatness tolerance for the finished floor (± 1.5 mm over 3 m) is different from that of the bare slab (± 3 mm over 3 m). Don't mix them up.
150.Forgetting material waste: quantity calculations must always include a waste factor of 5 to 10%. Examiners often test this concept.
151.Neglecting electrical coordination: outlet boxes in raised access floors must be installed BEFORE panel placement, not after.
152.Using wood shims: leveling shims must be steel or plastic. Wood compresses and deforms with moisture.
153.Ignoring fire-stop requirements: cable penetrations in demountable partitions must be sealed with ULC-certified products. Simple caulking is not sufficient.
154.Confusing concentrated load and uniform load: concentrated load is applied over a small area (25 mm × 25 mm), uniform load over the entire surface. The values are not interchangeable.
155.Forgetting panel orientation: raised floor panels often have an installation direction indicated by an arrow on the underside. Follow this direction to ensure structural integrity.
156.Not checking slab moisture: a damp slab causes corrosion of metal pedestals and deformation of panels. Moisture must be below 4%.
157.Calculating the number of studs without adding the end stud: the formula is (length ÷ spacing) + 1. Forgetting the +1 is a classic error.
158.Ignoring accessibility requirements: doors in demountable partitions must have a minimum clear width of 850 mm according to the NBC.

Summary

Demountable partitions and raised access floors are essential modular systems in modern commercial buildings. To succeed on the Red Seal exam, remember the following key points:

Demountable partitions: non-load-bearing, modular, relocatable systems. Components: base plates, studs, rails, panels. Plumbness tolerance: 1.5 mm/m.
Raised access floors: technical floor systems with adjustable pedestals, stringers, and 600 × 600 mm panels. Flatness tolerance: ± 1.5 mm over 3 m.
Calculations: number of studs = (length ÷ spacing) + 1. Number of panels = total area ÷ panel area, plus 5% waste.
Standards: NBC for construction and fire safety, Canadian Electrical Code, Part I for wiring, CSA B149.1 for gas, CAN/ULC-S102 and S114 for fire.
Loads: minimum concentrated load of 3 kN with maximum deflection of 2.5 mm per CSA Z-101.
Safety: mandatory PPE, maximum lifting load of 23 kg, coordination with other trades.
Quality control: checks before, during, and after installation, documentation of deviations.

Master these concepts, calculation formulas, and code requirements, and you will be well prepared for the exam questions on this chapter.

Chapter 5Exterior Finishing and Building EnvelopeChapter 7Hardwood and Engineered Wood Flooring Installation

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