Residential Plumbing, Electrical, Ventilation—Residential Kitchens and Bathrooms

Every family has different needs. If a family entertains often, what size rooms do they need to accommodate the gathering? If there are several children, does each child need their own bedroom? How many bathrooms will the children need? Is there a family member with special needs? The questions are endless. To limit the design possibilities, the designer must identify the family’s most important needs. Wants and desires of lesser importance can be considered later in the design process.

KITCHEN EQUIPMENT ELECTRICAL REQUIREMENTS

For any residential kitchen or bathroom, the electrical requirements and consideration of the loads is very important. Your design should show all the proposed locations of lighting fixtures, power outlets, and dedicated circuits for large individual appliances, and an electrician should confirm whether all of these features will function as intended. Like other professionals, any electrician will need to follow the most recent provision of their relevant reference codes; this usually includes the National Electrical Code (NEC).

The International Residential Code (IRC) should also come into play. Unlike the International Building Code, which covers buildings from a more general level, the IRC specifically focuses on topics involving home construction, applying to one- and two-family detached dwellings and apartment buildings up to three stories.

Besides some of the key facets of kitchens and bathrooms, like plumbing and electrical, it features sections on foundations, framing, mechanical, fuel, gas, and energy, in addition to a standalone set of standards. (Given all that, the IRC code is more complete than the residential code provided by the Council of American Building Officials, its only other predecessor code.)

Electricians usually determine the circuiting arrangements in residential work. For this, they’ll need to know the voltage requirements of large appliances and which lighting fixtures are low voltage, along with any other electrical requirements.

HOUSEHOLD CIRCUITS

Three types of circuits are used in residential households:

General lighting circuit: Serves lighting and wall receptacles; 3 watts per square foot of living area is required
Small appliance circuit: Distributes power to outlets for plug-in appliances (e.g., toasters, blenders); two 20-A circuits in the kitchen are required
Individual appliance circuit: Supports large appliances that are draw a large amount of current, requirements depend on the individual appliance

A rule of thumb for general lighting-circuit receptacles is to plan for twelve outlets for 15-A circuits, and sixteen outlets for 30-A circuits. Examples of devices that might require an individual appliance circuit include refrigerators, ovens, dishwashers, and garbage disposals. Due to the risk of using an electrical device while making contact with metal pipes or fittings that are grounded, kitchen and bath circuits should use a special type of circuit breaker known as a ground fault circuit interrupter, or GFCI breaker. The breaker senses the flow of current, and can cut the flow within a fraction of a second if it gets the signs of the current flowing through a person.

RESIDENTIAL WIRING

When planning a kitchen, it may help to remember the general requirements for residential electrical wiring systems:

SCHEMATIC DIAGRAM OF TYPICAL RESIDENTIAL ELECTRICAL LAYOUT

Schematic Diagram

Minimum of one wall-switch-controlled lighting outlet (see #1 above)
Convenience outlets installed so that no point along the floor is farther than 12 ft. (measured horizontally from an outlet; see #2 above)
Minimum of two #12 wire 20-A small-appliance circuits to serve only small convenience outlets, including refrigeration equipment (see #3 above)

For #3, both circuits must extend to the kitchen, although other rooms such as pantries, dining rooms, breakfast rooms, and family rooms may be served by one or both of them. No other convenience outlets may be connected to these circuits, except a receptacle installed solely for an electric clock. In kitchen and dining areas, convenience outlets must be installed at each and every counter space wider than 12 in.

LOADS, CIRCUITS, AND RECEPTACLES FOR RESIDENTIAL ELECTRICAL EQUIPMENT

APPLIANCE	TYPICAL CONNECTED VOLT‐AMPERES^a	VOLTS	WIRES^b	CIRCUIT BREAKER OR FUSE^c	OUTLETS ON CIRCUIT	NEMA^k DEVICE^dAND CONFIGURATION
KITCHEN
Range^e	12,000	115/230	3 #6	60 A	1	14–60R
Oven (built‐in)^c	4500	115/230	3 #10	30 A	1	14–30R
	6000	115/230	3 #10	30 A	1	14–30R
Dishwasher^c	1200	115	2 #12	20 A	1	5–20R
Waste disposal^c	300	115	2 #12	20 A	1	5–20R
Broiler^e	1500	115	2 #12	20 A	1 or more	5–20R
Refrigerator^f	300	115	2 #12	20 A	1 or more	5–20R
Freezer^f	350	115	2 #12	20 A	1 or more	5–20R

NOTES

Wherever possible, use actual equipment rating.
Number of wires does not include equipment grounding wires. Ground wire is #12 AWG for 20‐A circuit and #10 AWG for 30‐A and 50‐A circuits.
May be direct‐connected. For a discussion of disconnect requirements, see NEC Article 422.
Equipment ground is provided in each receptacle.
Heavy‐duty appliances regularly used at one location should have separate circuits. Only one such unit should be attached to a single circuit.
A separate circuit serving only one other outlet is recommended.
Should not be connected to a circuit with appliances or other heavy loads.
A separate circuit is recommended.
It is recommended that all motor‐driven devices be protected by a local motor‐protection element, unless motor protection is built into the device.
Connect through disconnect switch equipped with motor‐protection element.
National Electrical Manufacturers Association (NEMA).When working with single-family residential design, architects are also frequently required to consider Residential Plumbing, Electrical, Ventilations requirements in their design layouts. Architects are graphically oriented professionals and need quick access to potential engineering and appliance components that will adapt to a variety of overall floor plans. Now, AGS Online provides graphic illustrations for Residential Plumbing, Electrical, Ventilations in a downloadable format.

Vehicular Circulation Considerations—Residential Streets

Residential streets and highways are designed to accommodate a variety of vehicles, up to and including semitrailer trucks. When private driveways and roadways will serve only passenger vehicles, it may be appropriate in some instances to use smaller dimensions. Nevertheless, be certain private roads are wide enough to allow passage of fire and emergency vehicles.

When designing street layouts in residential developments, there are a number of important additional considerations, including safety. The underlying concept of the shared street system is one of integration, with an emphasis on the community and the residential user. Pedestrians, children at play, bicyclists, parked cars, and moving cars all share the same street space.

RESIDENTIAL STREETS AND GUIDELINES FOR HEALTHY NEIGHBORHOODS

When designing street layouts, especially suburban streets and neighborhoods, it’s important to avoid directing major traffic circulation through residential developments. Consider the following four key design criteria for use within residential areas:

Minimize the amount of internal travel while maximizing convenience of access to nonresidential activities
In any residential street layout, provide a series of spaces in which the road pavement plays an integrated function, as opposed to the typical linear pavement that just facilitates automobile movement
Residential streets are regularly used as play areas, so design them to reflect a pedestrian orientation rather than only to facilitate vehicular movement
Set the radius of cul‐de‐sacs to the minimum required to accommodate emergency and maintenance vehicles, while considering alternative turnarounds

TRAFFIC CALMING IN RESIDENTIAL DEVELOPMENT

Traffic calming improves neighborhood livability and the pedestrian environment by reducing vehicle speeds and noise, visual impacts, and through‐traffic volumes. Traffic calming includes a variety of design techniques and traffic management programs:

Vertical changes to the road (e.g., speed bumps and humps, raised intersections, etc.)
Lateral changes in the road (e.g., chicanes, narrowing, traffic diverters, etc.)
Traffic circles
Small corner radii
Gateway features
Related streetscaping (street furniture, lighting, landscaping, etc.)
Queuing

For streets of up to 750 vehicles per day, traffic and delay considerations do not necessitate the need for more than one traffic lane. A single‐lane configuration is sufficient if parking lanes are incorporated or passing places are provided. For example, the width of residential streets may be as narrow as 20 ft. with parking on one side. Through careful design, this can produce cost savings in grading, drainage, and street construction, and lessen the amount of impervious surfaces.

DESIGN CONCEPTS AND GUIDELINES FOR RESIDENTIAL SUBDIVISION PLANNING

A number of different design concepts may be implemented to help preserve the residential feel when applying street design guidelines for healthy neighborhoods. They can range from on-street parking and shared streets, to more nuts-and-bolts features like sufficient vehicle turning radii and fire vehicle access.

On-Street Parking

On‐street parking should be encouraged whenever possible, as it is a highly efficient form of parking, especially where higher housing densities and a compact neighborhood are desired. On‐street parking should be especially encouraged near the center of the neighborhood planning area, closest to the neighborhood focal point, services, transit stops, and so on. On‐street parking also provides an important physical and psychological buffer between pedestrians on the sidewalk and traffic. The commonly held perception that on‐street parking will create situations where children dart from behind a parked car into passing traffic is not borne out by actual experience.

Shared Streets

The underlying concept of the shared street system is one of integration, with an emphasis on the community and the residential user. Pedestrians, children at play, bicyclists, parked cars, and moving cars all share the same street space. Even though it seems these uses conflict with one another, the physical design is such that drivers are placed in an inferior position. Through geometrical and physical changes in the street cross section and its physical appearance, motorists sense that they are intruding into a pedestrian zone and drive more slowly and cautiously. By redesigning the physical aspects of the street, the social and physical public domain of the pedestrian is reclaimed.

Alleyways

Alleys eliminate the demand for automobile access to the property from the front, reduce the need for curb cuts, and reduce the number of parking garages oriented to the street. Alleys also provide an excellent alternative for utility easements and service access. The typical alleyway right‐of‐way width is 15 to 20 ft., with pavement typically covering the full width of the right of way.

Sufficient Vehicle Turning Radii

The vehicle to be accommodated—the design vehicle—is an important control in the design of urban streets. The most important characteristic of the design vehicle, its turning radius, dictates intersection design. For urban streets, four design vehicles are defined in the American Association of State Highway and Transportation Officials (AASHTO) Green Book.

Vehicle turning radii, as established by AASHTO, are based on broad categories of vehicle types, each of which encompasses a wide variety of actual vehicles on the road. Information on passenger vehicle dimensions for parking design, provided below, provides a more detailed breakdown of vehicle types within the various categories. For off‐street design applications, such as parking and driveways, the more detailed versions are appropriate. For public streets, the AASHTO templates are definitive.

Design Vehicle Dimensions

VEHICLE	LENGTH (L) (ft.‐in.)	WIDTH (W)	HEIGHT (H)	WHEELBASE (WB)	OVERHANG FRONT (OF)	OVERHANG REAR (OR)	GROSS WEIGHT (LB)
Small car¹	14‐9	5‐9	4‐4	8‐5	2‐0	4‐6	3300
All cars	16‐6	6‐1	4‐8	9‐0	2‐6	4‐5	3300
Light truck	18‐11	6‐8	6‐5	11‐5	2‐9	4‐0	6750
Van	18‐8	6‐7	6‐10	11‐3	2‐9	4‐0	7100
Sport/utility vehicle	16‐7	6‐7	6‐2	9‐8	3‐0	3‐8	7000
Sport wagon	15‐8	7‐1	5‐11	8‐10	2‐6	4‐4	5950
Composite passenger vehicle²	17‐2	6‐7	7‐6	9‐11	3‐0	4‐4	6300
Wheelchair lift van (personal use)	17‐8	6‐8	8‐0	11‐6	2‐6	3‐8	6000
Boat trailer	20‐0	8‐0	6‐0	See detail	3‐0	8‐0	4000
RV–conventional trailer	27‐0	7‐0	9‐0	See detail	3‐0	8‐0	4000
RV–fifth wheel (pickup‐based)	34‐0	8‐6	12‐0	8‐0	22‐0	12‐2	3500
RV–folding trailer	16‐0	7‐6	5‐0	—	8‐6	7‐6	1500
Slide‐in pickup camper	18‐11	10‐0	7‐3	—	—	—	2900
Stretch limousine	24‐6	6‐0	5‐0	15‐6	4‐0	5‐0	9000
Shuttle van (11 passengers)	20‐0	6‐6	6‐10	11‐6	3‐0	5‐6	11,000

Notes:

Small car classes 5 through 7, per Parking Consultants Council (PCC).
A composite passenger vehicle is a design vehicle that encompasses passenger cars, light trucks, vans, and sport/utility vehicles. It is the vehicle for which a parking facility should be designed.

Fire Apparatus Access

According to the U.S. General Services Administration, in its post on site circulation design, ground-level and aerial access for fire department vehicles is an important component of planning. Access for vehicles should be provided, and the local fire department should be consulted regarding the specific requirements for the following:

surface material of the access roadway(s)
minimum width of fire lane(s)
minimum turning radius for the largest fire department apparatus
weight of largest fire department apparatus
minimum vertical clearance of largest fire department apparatus.

Buildings or portions of buildings exceeding 30 ft. in height from the lowest point of fire department vehicle access shall be provided with access roads capable of accommodating fire department aerial apparatus.

Bathrooms and Layouts—Residential Bathroom Design

The International Residential Code has numerous code requirements for bathroom design. Section R307 provides spatial requirements, including minimum fixture clearances and wall materials for bathtubs and shower spaces. Other code requirements related to plumbing, mechanical, and electrical issues in a bathroom space are in other sections of the code.

Typical bathroom accessories include a medicine cabinet, mirror, soap dish, toilet paper holder, towel bar, and linen storage space. A general guideline is to allow between 24 and 36 in. of towel bar space for each family member using the bathroom.

FIXTURE SIZES AND CLEARANCES

FIXTURE	A		B		C		D		E
FIXTURE	MINIMUM	LIBERAL	MINIMUM	LIBERAL	MINIMUM	LIBERAL	MINIMUM	LIBERAL	MINIMUM	LIBERAL
Water closet	27″	31″	19″	21″	15″^*	18″	15″^*	22″	21″^*	36″
Bidet	25″	27″	14″	14″	15″^*	18″	15″^*	22″	21″^*	36″
Lavatory	16″	21″	18″	30″	2″	6″	14″^*	22″	21″^*	30″
Shower (interior dimension)	30″^*	36″	30″^*	36″	2″	8″	24″^*	34″	N/A	N/A
Bathtub	60″ standard	72″	30″ standard	48″	21″	34″	^**		^**

*Designates code requirement **Designates “As required by other fixtures”

RESIDENTIAL BATHROOM DESIGN BASICS

When planning the layout and function of residential bathroom accessories, consider the entire bathroom layout. The primary components of any residential bathroom should be fairly familiar:

bathtubs and showers
plumbing fixtures
toilet, bath, and laundry accessories

Bathtubs

Bathtubs are available in many shapes, sizes, and styles, including rectangular, corner, and oval. Three types of installation are common: recessed, drop‐in, and freestanding. Materials for bathtub surrounds include ceramic tile, solid surfacing, molded fiberglass, and acrylic one‐piece units. The surround material is important for coordination purposes during installation. Bathtubs are available in several different materials , though the fiberglass and acrylic units are the most common.

Showers

Showers can be included with bathtubs or be separate fixtures. A bathtub-and-shower combination usually shares a water supply valve. The shower surround may be part of the bathtub or site built. Shower enclosures are generally three sided, with an impervious finish. A shower door or curtain completes the enclosure. These enclosures, also known as “shower stalls,” consist of a floor receptor topped by water‐resistant walls. Receptors may be manufactured or site built and are designed to slope to the drain. The enclosure walls may be either self‐supporting or attached to the house framing.

Plumbing Fixtures

A plumbing fixture is a device or appliance designed to supply water or to receive waterborne waste, and may discharge into a sanitary waste system. Ideal fixture materials should be nonabsorbent, nonporous, nonoxidizing, smooth, and easy to clean. Plumbing codes usually mandate the number and type of fixtures that must be provided for specific occupancy, based on the capacity. Provisions for people with disabilities have been made an integral part of code requirements, which mandate the quantity and design of spaces utilizing plumbing fixtures.

Plumbing fixtures include faucets and sinks, and water closets (toilets) and bidets.

Typical Water Supply and Drainage from a Plumbing Fixture

Bathroom Accessories

Medicine Cabinets

Medicine cabinets can be specified with either left‐ or right‐hand door swings, and are typically available in both surface-mounted or recessed styles. Side-access medicine cabinets eliminates the need to reach over a counter.

Mirrors

Mirrors located above lavatories, sinks, and vanities must be mounted with the bottom edge of the reflecting surface 40 in. maximum above the floor. Other mirrors must be mounted with the bottom edge of the reflecting surface 35 in. maximum above the floor.

Tilting mirrors that extend 4 in. from the wall at the top and 1 in. at the bottom are available in widths of 16, 18, and 24 in. and heights of 30 and 36 in. A full‐length mirror can accommodate most people, including children and wheelchair users.

Americans with Disabilities Act (ADA)/Architectural Barriers Act Accessibility Guidelines 2004 recommend that the top edge of mirrors should be 74 in. minimum from the floor to accommodate both ambulatory people and wheelchair users. The Guidelines require mirrors above lavatories or countertops to be installed with the bottom edge of the reflecting surface 40 in. maximum above the finished floor . Those not above lavatories or countertops are to be installed with the bottom edge 35 in. above the floor.

Soap Dishes

Soap dishes are available both in recessed and surface‐mounted styles, including heavy‐duty and vandal‐resistant versions. For commercial purposes, touch‐free automatic soap dispensers detect the user’s hands and dispense a small amount of soap, but these are generally not used in residential bathrooms.

Accessible soap dispensers over lavatories or countertops should be mounted no more than 42 in. above the finish floor. Pushbuttons may be mounted up to 48 in. high, depending on the depth of any obstruction to wheelchair use.

Toilet Paper Holders

In addition to clearance requirements, the United States Access Board, ICC/ANSI A117.1, and the ADA include provisions for the location and operation of flush controls and toilet paper dispensers. Manually operated flush controls must be located on the open side of the toilet; they may not be centered above the toilet. The hatched area in Figure “WATER CLOSETS” indicates the allowable location of the toilet paper dispenser. Dispenser outlets must be within the range shown. Dispensers should allow continuous paper flow, not control delivery.

Towel Bars

Residential bathrooms typically include two towel bar locations, one near the sink and another near the tub and/or shower. A general guideline is to allow between 24 and 36 in. of towel bar space for each family member using the bathroom.

Linen Storage Spaces

The options for residential bathroom storage, as with most storage spaces in a house, offer some amount of flexibility and an opportunity for creativity. Stainless steel shelves are available up to 28 ft. long, and are delivered and installed in multiple sections. Full‐extension drawer glides and pullout drawer storage below the counter allow for more accessible storage. Lever handles are more easily operated no matter the users’ age or ability.

The blog fix.com goes so far as to suggest the following storage solution in its post on bathroom design rules: “Most people think of bathroom storage as being under-cabinet space for toilet paper. But here is a novel concept: provide storage space separate from the vanity cabinet. Tall storage cabinets no more than 12” wide can fit in tight places and can satisfy most of your needs.”

Yearly Archives: 2019