Administration/019 Administration Dimensional Data Drawing Standards.pdf

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Index: Administration

Subject: (19) Dimensional Data Drawing Standards

Date: October 21, 2005

Revised March 30, 2020

 

GENERAL

• Units shall be drawn to scale, including components such as blowers, coils, heat exchangers, etc. Where one drawing is used for multiple units, the largest components that will be used in the cabinet should be shown.
• All drawings shall show an elevation (side) and plan (top) view; in some cases, other views may be necessary to clearly describe the unit layout.
• Unit orientation shall be airflow from right to left.
• All New and replacement units shall be drawn with the base @ 6” in height for standard units; Top shall be drawn @ 5” to leave an internal height of 11” less than unit overall height. For larger units, base height may increase and the internal height will decrease. The weight calculation will alert you when non-standard base height is required . (EXCEPTION: Consult drafting for units wider than 144”).
• Unless otherwise specified by Sales, duct flanges for side, end or top duct connections shall be shown as 2”.
• Any walk-in service vestibule must have a minimum of 78” height clearance to meet NEC requirements. Piping, conduit, lights, etc. cannot protrude into the clearance area.
• Stationary panels are not required for control panels that overhang the unit base by at least 4” (wire entry shall be through the bottom of the control panel).
• Standard control panels shall be drawn at an inside depth of 14”. For a single line drawing, the control panel shall be drawn at 17” to allow inner and outer wall thickness.
• Where “NEMA-3R” equivalent boxes are required, the box shall be shown on the drawing and drawn to scale. The box shall be labeled according to its intended purpose, such as “POWER WIRING CONNECTION”, “CONTROL WIRING CONNECTION”, etc.
• For new units, all chases shall be no less than 6” in either dimension (6” x 6” minimum).
• All variable speed drive (VSD) locations shall be shown and labeled on the dimensional data drawing. Please consult the [file:///H:/EngineeringProcedures/Cabinet/015_Cabinet_Installation%20Guidelines%20for%20VFDs.pdf Installation Guidelines for Variable Frequency Drives] engineering procedure to determine a suitable location and sizing direction.
• Power burners, blower motors, etc. shall be shown in the plan view as well as the elevation view to verify location.
• For all gas fired components, such as tubular furnaces, power burners, gas fired humidifiers, the exhaust flue(s) should be shown in the elevation view of the unit.
• For tubular furnaces, the heater controls shall be shown. Whenever possible, the heater controls should be located in a separate section from the furnace.
• Water and steam coil headers shall be shown in the plan view to verify coil orientation.
• Drawing file name shall be as described in a previous procedure.
• Drawing name block shall show the drawing file name and date the drawing was created. Revisions shall show the revision number and the revision date in the revision log in the lower left corner of the drawing title block.

 

DIMENSIONING/LABELING

• Unit overall dimensions (length, width, height) of the cabinet shall be dimensioned. In addition, an overall dimension including any component that cannot be removed for shipping will also be shown on the drawing so that the correct shipping status can be determined. Units with top duct connections will be dimensioned to the top of the duct flange (consult Drafting to determine the proper overall height to show on the dimensional drawing).
• Dimensions shall be associated and shall NOT be exploded.
• All obstructions shown on field notes from the Seasons-4 unit shall be shown on the dimensional data drawing. If there are obstructions shown on the field measurement drawings that are not clearly dimensioned, the project engineer will request in writing that Sales provide the necessary clarification to get required details to accurately show obstructions of the Seasons-4 replacement unit on the dimensional drawing.
• If there a side or area that the customer has identified as inaccessible, a note shall be added to the drawing to indicate “NO ACCESS THIS SIDE (OR AREA)”.
• All unit splits must be dimensioned and labeled as “UNIT SPLIT”, and a dashed line should be shown between the plan and elevation views at the split line.
• All required electrical entry points (stationary panel or chase) to the units must be labeled. Where a single point of entry for power and controls is provided, it shall be labeled as “ELECTRICAL”. Where power and controls entry is two separate locations, they shall be labeled as “POWER” and “CONTROLS”.
• All chases/openings shall have size shown and must be dimensioned for location on the unit.
• Stationary panels shall be 6” in height in the air handling section or the condensing section, unless specified otherwise by Sales. Labeling on the drawing will include the specified height of the stationary panel.
• All louvers/protrusions from the unit shall be dimensioned: O.A. louvers @ 8” as standard, E.A. louvers @ 6” as standard. If O.A. hoods are required in addition to louvers, these also shall be shown and dimensioned @ 12” as standard.
• Doors shall be indicated as outlined in a previous procedure. Note that control panels wider than 36” will require two access doors.
• Viewport (window) locations shall be indicated on the dimensional data drawing.
• Light locations for additional lights shall be indicated on the dimensional data drawing. Standard service vestibule or control panel light does not have to be shown.
• Gas connection stub-out locations will not be dimensioned. If the gas connection is through a chase, the chase will be dimensioned as outlined previously.
• If the gas connection is coming up in a common chase with any electrical connections, a partition must be added to isolate the gas piping from the electrical section. This chased off area around the gas piping must be open at the top into the gas furnace section according to code so that gas cannot be trapped inside.