## 1.7 Scope and Application

The Energy Standards apply to both nonresidential and residential buildings. This manual addresses the requirements for nonresidential buildings, including hotels, motels, and high-rise residential buildings (those over three stories above grade in height). The Residential Manual discusses the requirements for low-rise residential buildings.

### 1.7.1 Building Types Covered

The nonresidential standards apply to all California Building Code (CBC) occupancies of Group A, B, E, F, H, I, M, R, S, and U. If buildings are directly or indirectly conditioned, they must meet all mechanical, envelope, indoor, and outdoor lighting requirements of the standards. Buildings that are not directly or indirectly conditioned must only meet the indoor and outdoor lighting requirements.

The Energy Standards do not apply to CBC Group L. The standards also do not apply to buildings that fall outside the CBC’s jurisdiction, such as mobile structures. If outdoor lighting is associated with a Group L occupancy, it is exempt. If the outdoor lighting is part of any other occupancy groups listed, it must comply.

### 1.7.2 Historic Buildings

Exception 1 to §100.0(a) states that qualified historic buildings, as regulated by the California Historical Building Code Title 24, Part 8, or California Building Code, Title 24, Part 2, Volume I, Chapter 34, Division II, are not covered by the Energy Standards. §140.6(a)3Q and Exception 13 to §140.7(a) clarify that indoor and outdoor lighting systems in qualified historic buildings are exempt from the lighting power allowances only if they consist solely of historic lighting components or replicas of historic lighting components. If lighting systems in qualified historic buildings contain some historic lighting components or replicas of historic components, combined with other lighting components, only those historic or historic replica components are exempt.

The California Historical Building Code (CHBC) Section 102.1.1 specifies that all non-historical additions must comply with the regular code for new construction, including the Energy Standards. CHBC Section 901.5 specifies that when new or replacement mechanical, plumbing, and/or electrical (including lighting) equipment or appliances are added to historic buildings, they should comply with the Energy Standards, including the Appliance Efficiency Regulations.

The California State Historical Building Safety Board has final authority for interpreting the requirements of the CHBC and determining to what extent the requirements of the Energy Standards apply to new and replacement equipment and other alterations to qualified historic buildings. In enacting the CHBC legislation, the Legislature wants to encourage energy conservation in alterations to historic buildings (Health and Safety Code Section 18951).

Additional information about the CHBC can be found at:

http://www.dgs.ca.gov/dsa/AboutUs/shbsb.aspx.

Contact the State Historical Building Safety Board at (916) 445-7627.

### 1.7.3 Low-Rise Residential Buildings

The residential energy standards cover single-family and low-rise residential buildings (occupancy groups R1, R2, and R3) and CBC Group U buildings including:

1. All single-family dwellings of any number of stories.

2. All duplex (two-dwelling) buildings of any number of stories.

3. All multifamily buildings with three or fewer habitable stories above grade (Groups R-1 and R-2).

4. Additions and alterations to all of the above buildings.

5. Private garages, carports, sheds, and agricultural buildings.

#### Table 1-1: Nonresidential vs. Residential Energy Standards

Nonresidential Standards | Residential Standards
These standards cover all nonresidential occupancies (Group A, B, E, F, H, M, R, S or U), as well as high-rise residential (Groups R-1 and R-2 with four or more habitable stories), and all hotel and motel occupancies. | These standards cover all low-rise residential occupancies including:
Offices Retail and wholesale stores Grocery stores Restaurants Assembly and conference areas Industrial work buildings Commercial or industrial storage Schools and churches Theaters Hotels and motels Apartment and multi-family buildings, and long-term care facilities (Group R-2), with four or more habitable stories | All single family dwellings of any number of stories (Group R-3) All duplex (two-dwelling) buildings of any number of stories (Group R-3) All multi-family buildings with three or fewer habitable stories above grade (Groups R-1 and R-2) Additions and alterations to all of the above buildings
Note: The Energy Standards define a habitable story as one that contains space in which humans may live or work in reasonable comfort, and that has at least 50 percent of its volume above grade.

### 1.7.4 Scope of Improvements Covered

The Energy Standards apply to any new construction that requires a building permit, whether for an entire building, outdoor lighting systems, signs, or for modernization. The primary enforcement mechanism is the building permitting process. Until the enforcement agency is satisfied that the building, outdoor lighting, or sign complies with all applicable code requirements, including the Energy Standards, it may withhold the building or occupancy permit.

The Energy Standards apply only to the construction subject to the building permit application. An existing spaces that is "conditioned" for the first time, is an addition and the all existing components , whether altered or not, must comply with the Energy Standards (see §100.1 addition or newly conditioned space).

Other than for lighting, the Energy Standards apply only to buildings that are directly or indirectly conditioned.

### 1.7.5 Speculative Buildings

1.7.5.1 Known Occupancy

Speculative buildings of known occupancy are commonly built by developers. For example, if a big box retail center or an office building was built on speculation, the owner would know the ultimate occupancy of the space, but might not know the specific tenant. For this building, the owner has two compliance choices:

1. Declare the building to be unconditioned space, forcing tenants to be responsible for envelope, interior lighting, possibly some exterior lighting, and mechanical compliance. This option may be very costly as most envelope and mechanical measures are far more expensive when they are installed in the building after the shell is.

2. Include envelope compliance as well as mechanical and/or lighting compliance, when those systems are to be installed prior to leasing.

A potential pitfall with delaying envelope compliance is that tenants may have a difficult time showing compliance. An energy code update between the time of shell construction and energy compliance for a tenant improvement could make compliance more difficult. Constructing a big-box style building without skylights, where skylights are required under the prescriptive approach, will also create a compliance challenge (and possibly impose large retrofit costs). In most cases, delaying envelope increases construction costs. If a building is likely to be conditioned, some enforcement agencies require envelope compliance when the shell is constructed.

Section 1.7.12 has information about energy compliance for tenant improvements in existing buildings.

1.7.5.2 Unknown Occupancy

Speculative buildings may be built and the ultimate occupancy is determined only when the building is leased. The structure could be an office, a warehouse, a restaurant, or retail space. The Energy Standards treat these occupancies similarly. The major differences are the lighting and ventilation requirements. If, a tenant is not identified during the permitting time, the “All other areas” lighting power densities in Table 140.6-C are used.

Deferring compliance by calling the building unconditioned will cause problems when the first tenant installs mechanical space conditioning equipment.

### 1.7.6 Mixed and Multiple Use Buildings

1.7.6.1 Mixed Low-Rise Residential and Nonresidential Occupancies.

When a building includes both low-rise residential and nonresidential occupancies, the requirements depend on the percentages of conditioned floor of each occupancy type:

A. Minor Occupancy (Exception 1 to §100.0(f).) When a residential occupancy is in the same building as a nonresidential occupancy, and if one of the occupancies is less than 20 percent of the total conditioned floor area, the smaller occupancy is considered a “minor” occupancy. Under this scenario, the applicant may choose to treat the entire building as if it is the major occupancy for envelope, HVAC, and water heating compliance. Lighting requirements in §140.6 through §140.8 or §150.0(k) must be met for each occupancy separately. The mandatory measures that apply to the minor occupancy, if different from the major occupancy, would still apply.

B. Mixed Occupancy. When a residential occupancy is mixed with a nonresidential occupancy, and if neither occupancy is less than 20 percent of the total conditioned floor area, two compliance submittals are prepared, each using the calculations and documents of its respective standards. Separate compliance for each occupancy is an option when one of the occupancies is a minor occupancy.

1.7.6.2 Different Nonresidential Occupancies.

When a building consists of multiple nonresidential occupancies, they are considered separate occupancies. Most occupancies have the same envelope requirements. High-rise residential and hotel-motel guest rooms have different envelope requirements. Lighting and mechanical requirements vary among the various usage categories and are treated according to each appropriate occupancy type.

Example 1-1

Question

A 250,000 sq ft high-rise office building includes a small 900 sq ft apartment on the first floor that visiting executives use. Is the apartment required to meet the residential requirements of the Energy Standards, and if so, would it be high-rise residential or low-rise residential?

Answer

No. The apartment occupies less than 20 percent of the total conditioned floor area, so it is a minor occupancy and may be treated as part of the office occupancy. Since it is on the first floor of the building, it is technically a low-rise residential building. All the residential mandatory measures apply.

### 1.7.7 High-rise Residential

High-rise residential buildings (four habitable stories or more) are covered by this manual and the nonresidential Energy Standards.

The Energy Standards apply separately to the living quarters and to other areas within the building. Living quarters are those non-public portions of the building in which a resident lives. High-rise residential dwelling units must incorporate the envelope and mechanical elements of the nonresidential Energy Standards with the lighting and service hot water needs of residential buildings. Outdoor lighting, including parking lots and garages for eight or more vehicles, and for indoor or outdoor signs (other than exit signs), comply with the nonresidential Energy Standards. Exit signs comply with the Appliance Efficiency Regulations.

1.7.7.1 Mandatory Measures

Special requirements for how mandatory measures apply to high-rise residential buildings include:

1. Living quarters meet the indoor lighting requirements for residential buildings.

2. Outdoor lighting meets the applicable outdoor lighting requirements of the Nonresidential Energy Standards.

3. Indoor and outdoor signs (other than exit signs) must comply with the Nonresidential Energy Standards. Exit signs must comply with the Appliance Efficiency Regulations.

4. High-rise residential occupancies must meet setback requirements applicable to residential occupancies.

5. Readily accessible area switching controls are not required in public areas provided switches that control the lights in public areas are accessible to authorized personnel.

6 Automatic lighting shut-off controls are not required for living quarters.

1.7.7.2 Prescriptive Compliance

The following summarizes how the requirements apply to high-rise residential buildings:

1. The envelope must meet the prescriptive envelope criteria for high-rise residential buildings (Energy Standards Table 140.3-C).

2. Economizer controls ae not required in high-rise residential living quarters.

3. High-rise residential living quarters are exempt from nonresidential lighting power density requirements. Occupancies other than living quarters must comply with the nonresidential lighting standards.

4. Lighting within the dwelling units must meet the lighting requirements of §150.0(k) that governs lighting in all spaces (including kitchen lighting requirements) except closets less than 70 ft² floor area. See Chapter 6 of the Residential Compliance Manual.

5.

6. Water heating in living quarters must comply with the residential Energy Standards (§150.1(c)8).

1.7.7.3 Performance Compliance

The rules for high-rise residential performance compliance are identical to the performance compliance rules for all nonresidential buildings. The area of each function of a high-rise residence is input into approved compliance software along with its corresponding envelope, mechanical, and lighting features. The software calculates an energy budget (standard design compared to proposed design).

### 1.7.8 Hotels and Motels

This section discusses the similarities and differences between the requirements for a hotel/motel and other nonresidential or high-rise residential buildings.

Hotels or motels are in unique in that their design must incorporate a wide variety of occupancies and functions into one structure. The occupancies range from nonresidential occupancies to hotel/motel guest rooms. Design functions that affect guests range from the arrival experience created through the main lobby's architectural features to the thermal comfort of the guest rooms. Other functions that designs must address include restaurants, kitchens, laundry, storage, light assembly, outdoor lighting, and sign lighting, these structures can range from simple guest rooms with a small office, to a structure encompassing a small city. (§100.1 "HOTEL/MOTEL").

Like other occupancies, compliance is submitted for the features covered in the permit application only. The nonresidential areas must meet the envelope, mechanical, indoor lighting, outdoor lighting, and sign lighting portions of the nonresidential Energy Standards. The guest room portions of hotels/motels must meet the envelope, mechanical, and lighting provisions applicable only to hotels/motel guest rooms. Each portion of the building individually complies with the provisions applicable to that occupancy.

Since hotel/motels are treated as a mixture of occupancies covered by the Energy Standards, the concepts at the beginning of each chapter apply to hotels/motels as they would any other nonresidential occupancy.

1.7.8.1 Mandatory Measures

The mandatory measures for envelope, mechanical, indoor lighting, outdoor lighting, and sign lighting apply to hotels/motels. The following describes any special requirements or exceptions:

• Hotel/motel guest rooms must meet the applicable residential lighting standards.

• Outdoor lighting must meet the applicable outdoor lighting standards.

• Indoor and outdoor signs (other than exit signs) must comply with nonresidential Energy Standards. Exit signs must comply with the Appliance Efficiency Regulations.

• Hotel and motel guest room thermostats shall have numeric temperature settings.

• Readily accessible area switching controls are not required in public areas provided switches that control the lights in public areas are accessible to authorized personnel.

• Automatic lighting shut-off controls are not required for hotel/motel guest rooms.

1.7.8.2 Prescriptive Compliance

The prescriptive requirements for envelope, mechanical, and lighting apply to hotel/motels. The following prescriptive requirements are specific to hotel/motels:

• Hotel/motel guest rooms must meet the prescriptive envelope criteria for high-rise residential buildings rather than the prescriptive criteria for nonresidential buildings.

• Hotel and motel guest rooms are not required to have economizer controls.

• Guest rooms in hotel/motels are exempt from the lighting power density requirements. However, lighting must meet the residential requirements of §150.0(k).

• Each occupancy (other than guest rooms) in the hotel/motel must comply with the Nonresidential Lighting Standards.

• For compliance with water heating requirements, use the residential compliance.

1.7.8.3 Performance Compliance

The rules for performance compliance are identical to those for all other nonresidential and high-rise residential buildings. The area of each function of a hotel/motel is input into the approved compliance software along with its corresponding envelope, mechanical, and indoor lighting features. The computer software program calculates an energy budget (standard design compared to proposed design). The proposed design must be less than or equal to the standard design for the building to comply.

### 1.7.9 Live-Work Spaces

Live-work buildings combine residential and nonresidential uses within individual units. In general, the low-rise or high-rise residential requirements (depending on the number of habitable stories) apply since these buildings operate and are conditioned 24 hours per day. Lighting in designated workspaces is required to show compliance with the nonresidential lighting standards (§140.6).

### 1.7.10 Unconditioned Space

An unconditioned space is neither directly nor indirectly conditioned. Both the requirements for lighting and minimum skylight area apply to unconditioned space. Some typical examples of spaces that may be unconditioned:

• Enclosed parking structures

• Automotive workshops

• Enclosed entry courts or walkways

• Enclosed outdoor dining areas

• Greenhouses

• Loading docks

• Warehouses

• Mechanical/electrical equipment rooms

These spaces are not always unconditioned. The specifics of each case must be determined.

### 1.7.11 Newly Conditioned Space

When previously unconditioned space becomes conditioned, the space is an addition and all the building’s components must comply as if it were a new building.

This situation has potentially significant construction and cost implications. If an unconditioned warehouse is upgraded with a heating system, thus becoming conditioned space, the building envelope must comply with the current envelope requirements and the lighting system must be conform with the current lighting requirements, including mandatory wiring and switching. If the envelope has large windows, some may have to be eliminated or replaced with more efficient windows. If the lighting system is inefficient, new and more efficient fixtures might have to be installed.

This requirement is a potential consequence of an owner erecting a shell with no plans to condition it.

For example, the owner of an office building obtains a permit for the structure and envelope, but wants the tenants to handle conditioning and lighting improvements. If that owner claims unconditioned status for that building, the owner does not have to comply with the envelope requirements of the standards. The owner does have to demonstrate compliance with the lighting requirements. If a tenant is not identified for a multi-tenant space during the permitting time, the “All other areas” lighting power density allowances from Energy Standards Table 140.6-C shall be used. When the tenant applies for a permit to install the HVAC equipment, the envelope and any existing lighting to remain must fully comply with the requirements for the occupancy designated.

This is the only circumstance when systems, other than those subject to the current permit application, fall under the Energy Standards. If the building was initially designed in a way that makes compliance difficult, the building envelope may require expensive alterations to bring it into compliance.

Many enforcement agencies require the owner to sign an affidavit at the time of the initial building permit for the shell, acknowledging the potential difficulties of future envelope or lighting compliance.

To minimize difficulties, the recommended practice is to demonstrate energy compliance when the envelope is built and comply with the lighting systems during installation.

### 1.7.12 New Construction in Existing Buildings

Tenant improvements, including alterations and repairs, are new construction in an existing building. For example, the base building was constructed, but the individual tenant spaces were not completed. Tenant improvements can include work on the envelope, mechanical, or lighting systems. The system or systems being installed are new construction and must comply with some or all of the current standards depending on the extent of the changes (see following sections).

The only time systems other than those subject to the current permit application are involved is when the tenant improvement results in the conditioning of previously unconditioned space.

### 1.7.13 Alterations to Existing Conditioned Spaces

§141.0(b)

An alteration is any change to a building’s water heating system, space conditioning system, indoor lighting system, outdoor lighting system, sign lighting, or envelope that is not an addition. Alterations or renovations to existing conditioned spaces have their own rules for energy compliance.

In summary, the alteration rules are:

1. The Energy Standards apply only to those portions or components of the systems being altered (altered component). Untouched portions or components need not comply with the standards.

2. If an indoor lighting, outdoor lighting, or sign lighting alteration increases the energy use of the altered systems, the alteration must comply with the current standards.

3. Alterations must comply with the mandatory measures for the altered components.

4. New systems in the alteration must comply with the current standards.

5. An existing unconditioned building, where evaporative cooling is added to the existing unaltered envelope and lighting, does not need to comply with current standards.

6. Mechanical system alterations are governed primarily by the mandatory measures.

Beyond meeting all applicable mandatory requirements, alterations must also comply with applicable prescriptive requirements discussed in Chapters 3 through 8 or use the performance approach. Within the performance approach, the option to show changes to the existing building (existing and alteration) is explained in Chapter 11. Performance credit is given only for systems that are changing under the current permitted scope of work.

Example 1-2

Question

An owner wants to add less than 50 sq ft of new glazing in an old nonresidential building in climate zone 3. What are the applicable requirements for the new glazing?

Answer

Exception to §141.0(b)2Ai exempts up to 50 sq ft of added windows from the relative solar heat gain coefficient (RSHGC) and visual transformation (VT) requirements in Table 141.0-A. The new glazing must meet only the climate zone 3 U-factor requirement of 0.58.

Example 1-3

Question

A building owner wants to change existing lighting fixtures with new ones. Do the Energy Standards restrict the change in any way?

Answer

If more than 10 percent of the fixtures are replaced in the permitted space (excluding enclosed spaces where no new lighting fixtures are proposed), or the connected load is increased, the standards will treat this as a new lighting system that must comply with §141.0(b)2I. Any applicable mandatory requirement affected by the alteration applies. The mandatory switching requirements would apply to the improved system if the circuiting were altered. Appliance efficiency regulations requirements for ballasts would also apply.

Example 1-4

Question

A building owner wants to rearrange some interior partitions and re-position the light fixtures in the affected rooms. Do the Energy Standards apply to the work?

Answer

Each of the newly arranged rooms must have its own light switches. Since there is no change in the connected lighting load or the exterior envelope, only the mandatory light switching requirements would apply.

Example 1-5

Question

A building owner wants to rearrange some duct work and add some additional fan coils to an existing HVAC system to improve comfort. Do the standards apply to the work?

Answer

There would be no change in the load on the system nor any increase in its overall capacity, so the standards would not apply to the central system. Only the duct construction requirements apply to altered ducting.

Example 1-6

Question

A building owner wants to replace an existing chiller. No other changes will be made to the HVAC system. Do the Energy Standards restrict the change in any way?

Answer

The mandatory efficiency requirements would govern the efficiency of the new chiller. The other parts of the system are unchanged and unaffected by the Energy Standards.

Example 1-7

Question

A building has a high ceiling space and the owner wants to build a new mezzanine space. There will be no changes to the building envelope or the central HVAC system. There will be new lighting installed. How do the Energy Standards apply?

Answer

Since a mezzanine does not add volume, it is an alteration, not an addition. The existing systems are not affected unless they are altered. The new lighting must comply with all requirements of the standards. The envelope is unchanged, so there are no requirements for it. The mechanical system duct work is simply extended without increase in system capacity, so only the duct construction and insulation requirements apply.

### 1.7.14 Additions

§141.0(a)

An addition is any change to a building that increases floor area and conditioned volume. Additions involve the:

• construction of new conditioned space and conditioned volume;

• installation of space conditioning in a previously unconditioned space; or

• addition of unconditioned space.

Mandatory measures and either prescriptive or performance requirements apply. For conditioned space, the heating, lighting, envelope, and water heating systems of additions are treated the same as for new buildings.

If the existing mechanical system(s) is simply extended into the addition, Exception 1 to §141.0(a) applies. Unconditioned additions shall only comply with indoor, outdoor lighting, and sign lighting requirements of the Standards. Refer above to Section 1.7.11 for further discussion of previously unconditioned space.

There are three options for the energy compliance of additions under the Energy Standards:

Option 1 – Addition Alone

Treat the addition as a stand-alone building with adiabatic walls to conditioned space (§141.0(a)1 and §141.0(a)2Bi). This option can use either the prescriptive or performance approach. Adiabatic means the common walls are assumed to have no heat transfer between the addition and the adjacent conditioned space, and are ignored entirely.

Option 2 – Existing-Plus-Addition

Using performance compliance, model the combination of the existing building with the addition (§141.0(a)2Bii). IN this scenario, the proposed energy use is calculated based on existing building features that remain unaltered and all alterations (actual values of the proposed alterations) plus the proposed addition. The standard design (allowed) energy budget is calculated by approved software based on:

1. The existing building features that remain unaltered; and

2. All altered features modeled to meet requirements of §141.0(b); and

3. The addition modeled to meet requirements of §141.0(a)1.

If the proposed building energy use is less than or equal to the standard design energy budget, then the building complies. The standard design for any alterations to the existing lighting or mechanical systems is based on the requirements for altered systems in §141.0(b).

This compliance option will generally ease the energy requirements of the addition only if there are energy improvements to the existing building. It may allow the designer to make up for inefficiencies of the addition depending on the nature and scope of improvements to the existing building.

Option 3 – Whole Building as All New Construction

The existing structure combined with the addition can be shown to comply as a whole building meeting all requirements of the Energy Standards for new construction for envelope, lighting and mechanical. This is the most stringent and is only practical if the existing building will be improved to the overall level of the current Energy Standards.

Example 1-8

Question

A restaurant adds a conditioned greenhouse-style dining area with very large areas of glazing. How can it comply with the standards?

Answer

Because of its large glass area, it will not comply on its own. By making substantial energy improvements to the existing building (envelope, lighting, and mechanical features), or by upgrading the existing building so that the entire building meets the requirements for new construction, it is possible for the combined building to comply. The performance approach would be used to model the entire building as an existing-plus-addition.

To accumulate enough energy credit that can be used to offset (trade off against) the large glazing area in the addition, several design strategies are available including:

1) Envelope improvements to the existing building which exceed the performance of the requirements in §141.0(b)1 and §141.0(b)2A and B; and/or

2) New indoor lighting in the existing building which has a lower installed lighting power density (LPD) than the allowed LPD in §140.6; and/or,

3) Existing building mechanical system improvements that exceed the requirements of §141.0(b)2C, D, and E.

### 1.7.15 Change of Occupancy

A change of occupancy alone does not require any action under the Energy Standards. If alterations are made to the building, then the rules for alterations or additions for the new occupancy apply (see Sections 1.7.13 and 1.7.14).

If no changes are proposed for the building, consider the ventilation requirements of the new occupancy. For example, if a residence is converted to a hair salon, with new sources of indoor pollution, existing residential ventilation rates would likely be inadequate. The Energy Standards requires no changes.

### 1.7.16 Repairs

A repair is reconstructing or renewing any part of an existing building for the purpose of its maintenance. Repairs shall not increase the preexisting energy consumption of the required component, system, or equipment. The Energy Standards do not apply to repairs.

Example 1-9

Question

If a space were 1,000 sq ft, how large would the heating system have to be to make the space directly conditioned?

Answer

The heating system would have to be larger than 10 British thermal units (Btu)/hour (hr)-sq ft =(hr-ft²) x 1,000 sq ftft² = 10,000 Btu/hr output to meet the definition of directly conditioned space.

Example 1-10

Question

A water treatment plant has a heating system installed to prevent pipes from freezing. The heating system exceeds 10 Btu/(hr-sq ftft²) and operates to keep the space temperature from falling below 50 degrees °Fahrenheit (°F). Is this plant directly conditioned?

Answer

Not if the heating system is sized to meet the building load at 50°F and is thermostatically controlled to prevent operating temperatures above 50°F. The definition of directly conditioned space excludes process spaces that have space conditioning designed and controlled to be incapable of operating at temperatures above 55°F at design conditions. Under these conditions, the space is not directly conditioned.

Example 1-11

Question

A process load in a manufacturing facility is generating heat inside the building shell. The manufacturing facility will install space cooling to keep the temperature from exceeding 90°F. If the thermostat will not allow cooling below 90°F (i.e., the temperature is kept at 90°F all the time), is this facility directly conditioned, if the mechanical cooling exceeds 5 Btuh/hr-sq ft?

Answer

No, this facility is not a directly conditioned space. The definition of directly conditioned space excludes spaces where the space conditioning system is designed and controlled to be incapable of operating at temperatures below 90°F at design conditions.

Example 1-12

Question

A natural gas kiln in a factory is in the building shell and its capacity exceeds 10 Btu/(hr-sq ft). Is the space within the shell considered directly conditioned space if there is no HVAC system installed in the building?

Answer

No. Since the heat from the kiln is an exempt process load and not part of heat that is transferred across

the building envelope components, and there is no HVAC system installed, the space is not considered a directly conditioned space and the shell does not have to meet the Energy Standards envelope requirements; however, the space must still meet the lighting requirements of the Energy Standards.

Example 1-13

Question

If in example above mechanical cooling with the capacity that exceeds 5 Btu/hr-sq ft is added to the building to keep the temperature from exceeding 85°F, does the space considered directly conditioned and must the envelope meet the Energy Standards requirements?

Answer

No, the definition of directly conditioned space excludes conditioning for process loads.

Example 1-14

Question

If a computer room is cooled with the capacity that exceeds 5 Btu/hr-sq ft and is controlled to a temperature of 75°F, does the space have to meet the envelope requirement of the Standards?

Answer

No. Computer rooms are a Covered Process. There are no envelope requirements in either §120.6 or §140.9.

Example 1-15

Question

The accompanying sketch shows a building with three unconditioned spaces (none has a direct source of mechanical heating or cooling). The air transfer rate from the adjacent conditioned spaces is less than three air changes per hour. The area weighted heat transfer coefficients of the walls (UA) are shown on the sketch. The roof/ceiling area weighted heat transfer coefficients (UA) for each of the three unconditioned spaces is 90 Btu/hr -°F.

Are any of these spaces indirectly conditioned?

Answer

Because the air change rate is low, each space is evaluated on the basis of heat transfer coefficients through the walls and roof. It is further assumed that the floors are adiabatic. The heat transfer will be proportional to the area weighted heat transfer coefficients of the walls and roof/ceilings.

SPACE A: The area weighted heat transfer coefficient to directly conditioned space is 3 x (75 Btu/hr-°F) = 225 Btu/hr-°F. The area weighted heat transfer coefficient to the outdoors or to unconditioned space is 70 Btu/hr-°F + 90 Btu/hr-°F = 160 Btu/hr-°F. Since the heat transfer coefficient from Space A to the conditioned space is greater than heat transfer coefficient from Space A to outside, Space A is considered indirectly conditioned.

SPACE B: The area weighted heat transfer coefficient to directly conditioned space is 75 Btu/hr-°F. The area weighted heat transfer coefficient to the outdoors or to unconditioned space is (3 x 70 Btu/hr-°F) + 90 Btu/hr-°F = 300 Btu/hr-°F. Since the heat transfer coefficient from Space B to the conditioned space is less than the heat transfer coefficient from Space B to outside, Space B is considered unconditioned.

SPACE C: The area weighted heat transfer coefficient to directly conditioned space is (2 x 75 Btu/hr-°F = 150 Btu/hr-°F. The area weighted heat transfer coefficient to the outdoors or to unconditioned space is (2 x 70 Btu/hr-°F) + 90 Btu/hr-°F = 230 Btu/hr-°F. Since the heat transfer coefficient from Space C to the conditioned space is less than the heat transfer coefficient from Space C to outside, Space C is considered unconditioned.

Example 1-16

Question

In a four-story building, the first floor is retail, second and third floors are offices, and the fourth floor is residential. Is the residential space high-rise or low-rise?

Answer

It is a high-rise residential space. Even though there is only one floor of residential occupancy, the building has four habitable stories, making it a high-rise building.