3.7 Drawings & Specifications

Before selecting and deploying access equipment on a project, apprentices must be able to read construction drawings, interpret specification documents, understand common drawing notations, and extract the information needed from manufacturer load charts and reach diagrams.

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Drawings 📄Specification
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Documents

3.7.1 Construction Drawings Relevant to Access Equipment

Four types of construction drawings provide the information needed to plan safe and effective access equipment deployment on an HVAC-R project. Each drawing type answers different questions about where, how high, and how much load the equipment must handle.

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Floor Plans

Overall building layout, room dimensions, and ceiling heights to determine the required working height range.
Location of mechanical rooms, rooftop access hatches, and equipment pads — identifying where access equipment must be positioned.
Structural column grid to identify potential scaffold anchor points and floor load-bearing areas.

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Elevation Drawings

Vertical heights of walls, ceilings, and roof structures to select correct equipment height range.
Parapet heights, equipment curb heights, and clearance dimensions critical for aerial lift reach calculations.

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Structural Drawings

Floor slab and structural member load ratings — critical when planning to position heavy scaffolds or aerial lifts on upper floors or parking structures.
Anchor and tie-in locations for scaffold connections to the building structure (required per CSA Z797).

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Mechanical Drawings (HVAC Plans)

Duct routing elevations and pipe routing to determine where overhead work will occur and what height must be reached.
Equipment schedules showing dimensions and weights of units to be installed — used to calculate platform load requirements before selecting equipment.

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Read Drawings Before Ordering Equipment Many access equipment errors — bringing the wrong boom length, selecting a lift that cannot fit through the building's access route, or exceeding a floor's load rating — are preventable by reviewing the relevant drawings before the job starts. Make drawing review part of your standard job-planning routine.

3.7.2 Specification Documents

Project specifications (written in CSI MasterFormat) supplement the drawings by defining standards, procedures, and requirements in text form. Two divisions are particularly relevant to access equipment on HVAC-R projects.

Division 01 — General Requirements

Site-specific safety requirements that apply to all trades on the project.
Scaffold erection standards and the specific CSA or ANSI standards the contractor must comply with.
Working-at-heights permit procedures and documentation requirements.

Division 23 — HVAC

Equipment installation procedures that may specify access requirements for installation sequences.
References to manufacturer installation manuals that define required access clearances (e.g., "minimum 3 m clearance above the unit required during installation").

Manufacturer's Installation Manuals

Define specific access requirements for the equipment being installed — not just preferred, but required clearances for safe installation.
Failure to follow manufacturer access requirements may void equipment warranties and create regulatory liability.

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Specs Govern When They Conflict with Drawings In the event of a discrepancy between drawings and specifications, the specifications typically govern. Always flag conflicts between drawings and specs to your supervisor before proceeding — never assume one takes precedence without confirmation.

3.7.3 Common Drawing Symbols & Dimensions

The following notations appear frequently on construction drawings. Understanding them is essential for extracting the height, clearance, and load information needed to plan access equipment correctly.

Symbol / Notation	Meaning	Relevance to Access Equipment
AFF / ABF	Above Finished Floor / Above Bottom of Floor	Determines the height from the finished floor surface to the work point — directly sets required equipment working height.
CLG HT / CH	Ceiling Height	Maximum headroom available; limits the extended height of scissor lifts and boom lifts in enclosed spaces.
CL (⊄)	Centreline	Reference datum for equipment positioning and scaffold bay layout.
EQ	Equal spacing	Used in scaffold layout drawings to specify uniform bay spacing — relevant to scaffold load table selection.
U.N.O.	Unless Noted Otherwise	The default dimension applies to all similar conditions unless a specific note overrides it. Critical for clearance assumptions.
TYP	Typical	The condition or dimension shown applies to all similar locations on the drawing — don't re-measure every identical location.
MAX / MIN	Maximum / Minimum	Critical dimensional limits for clearance calculations and load planning — these are hard limits, not guidelines.

3.7.4 Reading Lift & Scaffold Manufacturer Documentation

Manufacturer documentation for access equipment provides the critical performance data needed to safely configure and load the equipment for each specific job. Three document types are most commonly referenced in the field.

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Load Charts (Aerial Lifts)

Aerial lift load charts specify the maximum rated platform load at various boom angles and extension lengths. As the boom extends further outward, the allowable platform load decreases due to the increased tipping moment applied to the machine's chassis.

The operator must consult the load chart for the specific machine configuration (boom angle + extension) before loading the platform.
The load chart is physically posted on the machine; if the decal is missing or illegible, the machine must be taken out of service until it is replaced.
Never assume the rated platform capacity applies at all boom positions — it only applies in the stowed or near-stowed position.

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Scaffold Load Tables

Scaffold system manufacturers publish load tables specifying the maximum bay load (expressed in kPa or psf) for a given combination of frame spacing, plank span, and tier height.

Load tables must be consulted when designing a scaffold layout that will support heavy materials (refrigerant cylinders, duct sections, compressors).
Increasing frame spacing or plank span reduces the allowable load per bay — always check the table for the actual configuration to be built, not just the nominal system rating.

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Reach Diagrams (Work Envelope Diagrams)

Boom lift reach diagrams show the full range of platform positions achievable at various boom angles and extensions from the machine's ground position.

When planning access to a specific elevated point, the reach diagram confirms whether the machine can reach the target location from the available ground position.
Critical for determining the ground setback distance required to access a point at a given height — essential for rooftop work near parapet walls.
The reach diagram also shows dead zones — areas the platform cannot reach — helping identify when a different machine or ground position is needed.

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Documents Are Part of the Regulatory Framework Under CSA B354 (Elevating Work Platforms) and CSA Z797 (Access Scaffold), the manufacturer's documentation forms part of the regulatory compliance framework for that specific piece of equipment. Using equipment outside the parameters defined in these documents constitutes a regulatory violation in addition to a safety hazard.