1 HVACR116 – Trade Skills Mechanical Drawings. 2 Objectives After completing this unit, you will...

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HVACR116 – Trade Skills

Mechanical DrawingsMechanical Drawings

ObjectivesObjectives

• After completing this unit, you will be able to perform the following tasks:o Identify and briefly describe the major pieces of HVAC

equipment to be used in a buildingo List the sizes of pipes and fittings shown on mechanical

plans, and explain the major functions of eacho Describe the sizes and shapes of air-handling ducts

shown on mechanical drawings

• After completing this unit, you will be able to perform the following tasks:o Identify and briefly describe the major pieces of HVAC

equipment to be used in a buildingo List the sizes of pipes and fittings shown on mechanical

plans, and explain the major functions of eacho Describe the sizes and shapes of air-handling ducts

shown on mechanical drawings

Heating, Ventilating, and Air Conditioning PlansHeating, Ventilating, and Air Conditioning Plans

• Systems for larger buildings are designed by an engineer specialisto Usually drawn on outline of building floor plan

Shows location of HVAC and plumbing equipmento Warm air heating ducts carry warm air to spaces and

returns cool air to the source Allows for inexpensive air-conditioning

• Systems for larger buildings are designed by an engineer specialisto Usually drawn on outline of building floor plan

Shows location of HVAC and plumbing equipmento Warm air heating ducts carry warm air to spaces and

returns cool air to the source Allows for inexpensive air-conditioning

Unit VentilatorsUnit Ventilators

• Unit ventilators mix room air and outside air to ventilate while warmingo Warmth is provided by hot water piped from boiler

Figure 40–1. Unit ventilator schedule.

Figure 40-2. Operation of a unit ventilator.

Figure 40–3. Schedules of cabinet unit heaters, unit heaters, and fan cabinet unit heaters.

Heating PipingHeating Piping

• A solid line indicates supply pipes• A dashed line indicates return pipes• Pipe sizes are indicated by callouts• Fittings are represented by symbols

Figure 40–4. Mechanical and plumbing symbols.

Figure 40–4. (continued)

Heating Piping (cont’d.)Heating Piping (cont’d.)

• When pipes need to drop down from the ceiling to the ventilators, they are shown in isometric views

Figure 40–5. This isometric drawing shows how the heating pipes drop down from the ceiling to the level of the ventilators.

Heating Piping (cont’d.)Heating Piping (cont’d.)

Figure 40–6. Noises are eliminated by allowing pipes to expand and contract.

Air-Handling EquipmentAir-Handling Equipment

• Unit ventilators introduce fresh air • Separate ventilation system removes stale air• A louvered grille receives air and channels it into a

Figure 40–7. Explanation of grille designations.

Air-Handling Equipment (cont’d.)Air-Handling Equipment (cont’d.)

• Fire dampers close off ducts if they get hot in a fire• Fire dampers close off ducts if they get hot in a fire

Figure 40–8. Fire damper for ductwork.

PlumbingPlumbing

• DWV system is more complex for a large building• DWV system is more complex for a large building

Figure 40–9. Riser diagrams for school fixtures.

Electrical DrawingsElectrical Drawings

ObjectivesObjectives

• After completing this unit, you will be able to perform the following tasks:o Explain the information found on a lighting plano List the equipment served by an individual branch circuit

using electrical plans, riser drawings, and scheduleso Explain the information on a schematic diagram

• After completing this unit, you will be able to perform the following tasks:o Explain the information found on a lighting plano List the equipment served by an individual branch circuit

using electrical plans, riser drawings, and scheduleso Explain the information on a schematic diagram

Electrical DrawingsElectrical Drawings

• Deal predominantly with circuitso Basic methods of showing electrical circuits:

Plan views Single-line diagrams Riser diagrams Schematic diagrams

• Deal predominantly with circuitso Basic methods of showing electrical circuits:

Plan views Single-line diagrams Riser diagrams Schematic diagrams

Plan ViewsPlan Views

• Shows exterior walls, interior partitions, windows, doors, stairs, cabinets, etc.o Also location of electrical items and circuitry

• Power circuit electrical floor plan shows electrical outlets and devices o Includes duplex outlets, specialty outlets, telephone,

fire alarm, etc.

• Shows exterior walls, interior partitions, windows, doors, stairs, cabinets, etc.o Also location of electrical items and circuitry

• Power circuit electrical floor plan shows electrical outlets and devices o Includes duplex outlets, specialty outlets, telephone,

fire alarm, etc.

Figure 41–1. Circuiting symbols.

Plan Views (cont’d.)Plan Views (cont’d.)

• Lighting circuit electrical floor plan shows light fixtures, emergency lighting, security lighting, and special lighting control

Figure 41–2. Reflected ceiling plan.

Plan Views (cont’d.)Plan Views (cont’d.)

• Electrical symbols simplify drafting and interpreting of drawingso Not standardized

Figure 41–4. Recommended electrical symbols.

Single-Line DiagramsSingle-Line Diagrams

• Electrical service, or electrical distribution raceway, may need concrete encasing for protection (i.e., duct bank)

Figure 41–5. Duct bank system.

Riser DiagramsRiser Diagrams

• Shows path of wiring or raceway from one level of a building to another o Wiring rises from one floor to the nexto Does not give equipment location o Power riser diagrams show typical building electrical

service and related components

• Shows path of wiring or raceway from one level of a building to another o Wiring rises from one floor to the nexto Does not give equipment location o Power riser diagrams show typical building electrical

service and related components

Figure 41–6. Typical riser diagram showing an overview of the building’s electrical service and related components.

Riser Diagrams (cont’d.)Riser Diagrams (cont’d.)

• A special riser diagram is used for many systems:o Fire alarmo Securityo Telephoneo Clocko Signals (e.g., bell)

Schematic DiagramsSchematic Diagrams

• Symbols and lines show how parts are connectedo Do not have to show

location

• Symbols and lines show how parts are connectedo Do not have to show

location

Figure 41–9. Schematic diagram and wiring diagram for a three-phase, ac magnetic, nonreversing motor starter.

SchedulesSchedules

• Used to systematically list equipment, loads, devices, and informationo Fixture schedule lists complete information about each

fixture on lighting plan Mark Make Volts Watts Lamp type and quantity Notes or remarks

• Used to systematically list equipment, loads, devices, and informationo Fixture schedule lists complete information about each

fixture on lighting plan Mark Make Volts Watts Lamp type and quantity Notes or remarks

Schedules (cont’d.)Schedules (cont’d.)

• Other schedules include:o Panel scheduleso Kitchen equipment scheduleso Receptacle scheduleo Equipment scheduleo Connect load schedule

SpecificationsSpecifications

• Items that establish intended design and required construction requirementso Contractors and installers must review contract

documents for conflicts and/or discrepancies between contract, specifications, and drawings

• Electrical specifications give quality of materials, installation, and testing requirements

• Items that establish intended design and required construction requirementso Contractors and installers must review contract

documents for conflicts and/or discrepancies between contract, specifications, and drawings

• Electrical specifications give quality of materials, installation, and testing requirements

1 HVACR116 – Trade Skills Mechanical Drawings. 2 Objectives After completing this unit, you will...

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