Reading Architectural Working Drawings Residential And Light Construction

How To Read Electrical Plans

Scale of Reflected Ceiling Plans

Reflected ceiling plans should be drawn at the same scale as the floor plans. Depending on the complexity of the project and ceiling treatment, the most common scale for residential and small commercial projects is i// = 1'-0" (1:50 metric) and V8" = 1'-0" (1:100 metric) for large commercial projects. The scale the ceiling plan is drawn at should be noted and placed directly below the drawing, either adjacent to or directly below the title. If an enlarged detail is needed to explain a feature in the ceiling, it is keyed with a note or symbol to a separate, larger-scale drawing.

The luminaires should be drawn as simple rectangles, squares, or circles that depict the actual fixture as closely as possible. Simplistic forms prevent clutter in the view for ease of recognition. In most cases, the lighting fixture is drawn to the scale of the actual fixtures. However, in some cases such as miniature spotlights, the size may have to be exaggerated, as the properly scaled unit would be too small to show up on the plan.

PARTIAL REFLECTED CEILING PLAN

Metal Stud Plan

Bulkheads Reflected Ceiling Plan

An enlarged detail of a blackout shade is drawn in section view and keyed to its location in the small-scale reflected ceiling plan.

Lighting fixtures are represented with symbols in the reflected ceiling plan and keyed to a legend showing specifications.

Drafting Standards for the Reflected Ceiling Plan

A reflected ceiling plan must clearly show all walls, partitions, and soffits that intersect with the ceiling. It should also specify changes in ceiling elevations and materials, such as lights, sprinklers, smoke detectors, and HVAC diffusers that attach to or penetrate the ceiling. In drafting reflected ceiling plans, the designer should reproduce the floor plan walls and openings such as doors and windows, but without showing items such as built-in cabinetry, plumbing fixtures, etc.

The lighting fixtures and other electrical features shown on the reflected ceiling plan are given symbols that are keyed to a legend. It is advisable to draw in all the electrical symbols on the plan before it is dimensioned or notes are added. If not, a symbol may fall on top of a dimension, thus requiring the dimension to be moved. Locate the light fixtures in the ceiling plan in accordance with the lighting design concept. Common types of light fixtures on the lighting plan include surface-mounted, recessed, pendant, and track-mounted.

On commercial projects where there is a suspended ceiling, the reflected ceiling plans would show any partitions that extend through the ceiling plane as well. The ceiling grid lines (called "T" bars) should also be shown. Other information included in the reflected ceiling plan are the ceiling materials, ceiling heights, ceiling slopes, changes in ceiling heights, locations of all lighting fixtures (including exit and emergency lights), air dif-fusers and vents, access panels, speakers, sprinkler heads (if used), and other items that touch or are part of the ceiling plane.

Next, the interior designer should determine how the lights in the space are to be switched. For residential or small commercial

Standard lighting and electrical symbols

Standard Electrical Symbols

The ceiling grid, as well as lights and other items located within it, are shown to scale.

Troffer Symbol Drawing

The ceiling grid, as well as lights and other items located within it, are shown to scale.

The switching can either be shown on the reflected ceiling plan or on the electrical lighting plan. The switching design should be based on how much individual control is needed and the function of the lighting. Energy conservation needs and maximum circuit loads within the circuits will also determine the number and location of the switches. Generally, switches are located near the door or opening leading into the space. Large spaces that have more than one entry may require multiple switching locations.

After locating the switches, determine which luminaires they should control and delineate this on the plan. This can be done in two ways, depending on the size and complexity of the lighting plan.

The first method is to draw a line from the wall switch to the fixtures it controls. This connecting line should be dashed and curved to distinguish it from other objects and items on the drawing. Curved lines are preferred, as straight lines may get mixed up with wall lines or other items that are drawn in the plan. The connecting curved line should touch the outlet or fixture symbol. The symbol for switches can be a simple S. If a particular lighting fixture is switched from two locations, the symbols will be S3 to indicate that three items (two switches and one lighting fixture) are connected electrically.

The second method of showing light-fixture switching is to assign a number or letter to the switch and to place this same number in or near the light fixture shown in the ceiling plan. This method is used primarily in commercial spaces, where there might be a lot of multiple switching and other items placed on the ceiling plan, so that the use of lines (the first method) could complicate the drawing.

How Read Architectural Drawing

After the interior designer lays out the lighting and switching, the drawing is given to an electrical engineer, who indicates the exact circuitry, wire sizes, and other specifications required for the electrical system. In residential spaces, the drawing might be given directly to the electrical contractor, as the circuitry and requirements here are not as complex as those in commercial work.

Designation of Materials

When preparing the reflected ceiling plan, the designer must call out types and locations of specific ceiling materials. This can be done by placing notes on the plan, or symbols that are referenced to a ceiling material legend. The two most common ceiling systems used are gypsum board ceilings that are attached to the structure above, and suspended acoustical ceilings. Other ceiling finishes might include wood facing, linear metal, or even exposed wood joists and beams. Dimensioning Reflected Ceiling Plans

As the reflected ceiling plans are generally drawn to a scale that matches the floor plans, there is no need for a lot of dimensioning on the plan, unless ceiling breaks or changes of materials occur where they are not obviously located at a door, wall, or column location. As long as the reflected ceiling plan is drawn to scale, the dimensions of the spaces and structure can be reserved for the floor plan. However, in some cases, the sizes of the units and the fixture locations do need to be dimensioned. This is particularly true for large expanses of gypsum board ceiling, where the scale cannot be as easily determined as in a gridded suspended ceiling assembly (where, for example, one can count units to locate the light fixture).

When dimensioning the reflected ceiling plan, either "finish" dimensions or "framing" dimensions can be used, but the choice must be noted on the plans. Elements such as recessed light troffers can be precisely located in the finished space. If a downlight in a gypsum wallboard ceiling is to be used, it generally is dimensioned to its center point so the electrical contractor knows where to install

Reflected Ceiling Plan Symbols

PARTIAL REFLECTED CEILING PLAN

sc: i/4"= r-o"

it. Alignment and direction of patterns might need to be dimensioned directly on the plan. In these instances, references should be given that are easily obtainable in the field. Dimensions should be referenced from the face of a wall, column, or imaginary centerline of a room, as illustrated in Figure 14-17.

Reflected Ceiling Plan Symbols Legend

The recessed down lights in this reflected ceiling plan are dimensioned in relation to each other and various wall elements and soffits.

Checklist for Reflected Ceiling Plans

General

Title the drawing, note its scale, and identify north (or reference direction).
If needed, develop a ceiling type material schedule and key it to the plan.
Develop a lighting symbol legend and locate it on the same sheet as the first reflected ceiling plan (if more than one is required), or on a nearby sheet.
Clean up the plan (or in CAD, turn off superfluous information) so the walls, spaces, and key codes are clear, dark, and very legible. Don't show items unless they are on the ceiling plane or intersecting it.
Draw in major soffits or openings above and call them out in a note, including attic access panels.
Pouche walls, if applicable.
Decide on the switching patterns of the light fixtures (if the interior designer has this responsibility) and show by the curved-line method or use of numbers/letters.
Cross-reference the reflected ceiling plan to other drawings (if applicable), carefully checking for accuracy and completeness of information.

Notations

Note where the ceiling level changes or slopes if this has a direct effect on the light fixtures and their installation.
Note special features, clearances, finished ceiling heights above finish floors, alignments, and other important items.
Cross-reference the plan with symbols and reference to the lighting schedule, details, and other drawings as needed.

Dimensions

Dimension the locations of light fixtures and changes in ceiling types that are not readily apparent. Locate to such items as columns or existing walls.
Dimension clearances, alignments, and other controlling factors.
Dimension lighting coves and other structural lighting, or create large-scale drawings of these and cross-reference.

Electrical Plans

Electrical plans can include electrical outlets, telephones, communication devices, and other items requiring electrical power. In small projects, these items can be shown together with the lighting. An example of this type of drawing is illustrated in Figure 14-18. On large commercial projects, the electrical plan, often referred to as a power or power/communication plan, shows the outlets and related electrical devices separately (Figure 14-19). In most cases, the plumbing fixtures and items such as cabinetry and other built-in items are shown in order to more closely coordinate the location of electrical power devices. In some instances, such as in open-office situations, designers also prefer to show the furniture, as many times it relates directly to the electrical outlet locations (Figure 14-20). The interior designer prepares the power plan and then forwards it to the electrical engineer to detail the circuitry, wire sizes, panel boxes, and other electrical specifications. On small residential plans, the drawing is given directly to the electrical contractor to install the work according to accepted practices.

The telephone and other communication systems are also generally shown on the electrical plan. Locations of telephones, public address systems, computer terminals, intercommunication devices, and security systems are the responsibility of the interior designer in consultation with specialists. The designer draws a power/communications plan that schematically shows where power is needed for special equipment. Symbols for electrical devices are generally keyed to a legend that is on the same sheet as the plan. The electrical engineer or other system specialists do most of the detailed specifications for these devices.

Commercial Electrical Plans

ELECTRICAL 4 LIGHTING PLAN

In large commercial projects, a separate electrical/power plan with a legend specifies outlets and circuitry. Many architectural features and other systems are left out so that the electrical plan can be easily read.

A power plan often includes telephone and other communication devices.

Electrical Legends And Plan For Drawings

Scale of Electrical Plans

Electrical plans in commercial spaces are generally drawn at the same scale as the floor plans. The most common scale for commercial projects is V8" = l'-O" (1:100 metric). However, in complex installations, the scale might be increased to V4" = l'-O" (1:50 metric). The scale the plan is drawn at should be noted and placed either adjacent to or directly below the title.

Drafting Standards for Electrical Plans

Electrical plans must show all interior and exterior walls, stairs, and large devices, such as furnaces, water heaters, etc., that require power. Built-in fixtures and cabinetry, such as in bathrooms and kitchens, should also be drawn to better locate the electrical outlets and other devices. The walls should be drawn with lighter line weights so they do not dominate the drawing. Locate the convenience outlets on the walls where they are to be mounted, and call out the dimension above the finished floor (A.F.F.). Remember to note any special requirements such as weatherproof (WP), split-wired, or special-purpose connections. Common electrical symbols are shown in Figure 14-21.

Designation of Materials

Electrical plans are primarily diagrammatic. Although they are drawn to a scale that matches the floor plans, the electrical devices are often too small to portray in the drawing at their exact scale. They are drawn as an oversize symbol to be easily recognized. To keep the drawing simple, materials such as finish flooring and other items are not delineated.

Dimensioning Electrical Plans

Electrical plans are drawn to a scale that generally matches the floor plans. There is no need for a lot of dimensioning on the electrical plan, as items can be located to scale on the floor plans. However, in some cases, electrical outlets and other devices do need to be dimensioned to accurately place them where they can be easily accessed when the building is occupied. This is particularly true for large expanses of wall where the scale cannot be accurately determined by scaling the drawing. In such instances, references should be given that are easily obtainable in the field, dimensioning from the face of a wall, column, or imaginary centerline of a room. If a horizontal dimension is not given for a wall outlet, the electrician will place it as close as possible to the designer's plan. The electrician might choose to attach the outlet to a wall stud rather than locating it between two studs if the designer has not dimensioned a specific location.

Although most electrical outlets do not need to be exactly located, there are some exceptions, such as in this bar area, where outlets must coordinate with equipment.

PARTIAL ELECTRICAL PLAN

Sketch Troffer

Checklist for Electrical Plans

General

Title the drawing, note its scale, and identify north (or reference direction).
Title the accompanying electrical schedule and key it to the plan.
Add notes to clarify any abbreviations that are not commonly recognized.
Clean up the plan (or in CAD, turn off superfluous information) so the walls, spaces, and key electrical codes are clear, dark, and very legible.
Cross-reference the electrical plan to other drawings and schedules, carefully checking for accuracy and completeness of information.

Notations

Note special situations, such as devices supplied by owner or others.
Note special features, clearances, outlet locations above finish floors, cabinetry, and other items.
Note alignments and other important items that affect the electrical plan.

Dimensions

Dimension location of outlets and changes in floor or wall types that affect the outlet installation.
Dimension outlets to walls, wall corners or intersections, and other items such as columns.
Dimension the appropriate outlets to the proper distance above the finished floor (A.F.F.).
Dimension clearances, alignments, and other controlling factors.

The mechanical systems of a building are commonly referred to collectively as the HVAC (heating, ventilating, and air-condition-ing) system. The HVAC system ensures that the occupants of a building are provided with a comfortable environment. The system does more than provide heating for winter and cooling for summer. It brings in fresh air, circulates it through the interiors, and exhausts stale air and odors. It can also treat air to control humidity, dust, pollen, and other undesirable conditions.

The plumbing system in a building serves a number of different functions, such as delivering water to people and machines through pressurization (water supply), and ejecting water to be removed through gravity (drainage). Plumbing serves three basic needs: it provides water for human consumption, sanitary drainage of wastes, and mechanical systems. Water might be used for equipment or serve an automated sprinkler system, as discussed later in this chapter under plumbing plans. Some commercial buildings might also have a storm drainage system that rids the roof or other areas of rainfall or flooding. Such systems are separate from the sanitary sewage piping and collect into a storm sewer or are routed to a curbside drainage. A building might also have a waterfall feature, fountain, pond, or other decorative element that has a specialized, recirculating water system.

Mechanical and plumbing drawings involve a lot of communication, coordination, and teamwork among the various design professionals and the contractors. The professional offices that produce the HVAC and plumbing drawings must be aware of one

Continue reading here: Mechanical And Plumbing Plans

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