Reference

NBS

Publi

cations A 11 10b Mlbfln

NBSIR 82-2554

v

Health and Safety Considerations

for Passive Solar Heated and

Cooled Buildings

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Washington, DC 20234

August 1 982

Prepared for U.S. Department of Energy

n—«?i ve and Hybrid Solar Energy Division

*"*“'00—' ' *-e of Solar Heat Technologies

2QQ tington, DC 20585

. U56

82-2554

1982

f\) i ATIOHAl. nUWItAU 09 STANDAims

UBJUJ3T

NBSIR 82-2554

HEALTH AND SAFETY CONSIDERATIONS

FOR PASSIVE SOLAR HEATED AND

COOLED BUILDINGS

F. Eugene Metz

James H. Pieiert

Patrick W. Cooke

SEP

\ \ \J\ • QC

><?

Center for Building Technology

and

William D. Walton

Center for Fire Research

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Washington, DC 20234

August 1982

Prepared for U.S. Department of Energy

Passive and Hybrid Solar Energy Division

Office of Solar Heat Technologies

Washington, DC 20585

7 1982

p

—

l o o

"assy

23-

U.S. DEPARTMENT OF COMMERCE, Malcolm Baldrlge, Secretary

NATIONAL BUREAU OF STANDARDS, Ernest Ambler. Director

ABSTRACT

This report discusses the nature of health and safety considerations in

applying solar passive technology to buildings and how they would be affected

by current building regulatory requirements. Health and safety considerations

associated with solar passive systems are discussed including; indoor air

quality; structural safety; fire safety; and environmental issues such as ventilation, illumination, temperature control, humidity and noise control. The

report also identifies technical issues and research needs associated with

health and safety concerns in passive solar technology.

Keywords: Buildings; building regulations; energy; enforcement; health and

safety; passive design; solar energy; standards.

iii
PREFACE

This research was conducted by the Building Economics and Regulatory Technology

Division of the Center for Building Technology, National Engineering Laboratory,

National Bureau of Standards (NBS). The work was sponsored by the U.S. Department of Energy as part of its effort to provide for the technical acceptance of

passive solar energy applications in buildings.

The use of solar energy by passive solar design and construction techniques is

generally perceived to be quite positive and certainly not a threat to health

and safety. There are, however, techniques that are being used and explored

that are potentially hazardous. This document attempts to identify and dis- cuss some of these problem areas.

Investigation of existing building codes and standards indicates that their

enforcement could restrict the application of some common passive techniques.

This study includes an analysis of the model building codes and related regulatory documents to determine the content of regulations which could adversely

impact widespread dissemination of the technology. This information is related

to health and safety issues which have been associated with passive systems

including fire safety, indoor air quality, physical hazards, and structural

safety. Special appreciation is extended to Mr. Robert Dikkers, Research

Coordinator, NBS Solar Technology Program, for guidance and encouragement

throughout this effort. Appreciation is also extended to Ms. Belinda Reeder

whose thorough technical review and suggestions were most valuable. The

assistance of the CBT Word Processing Center in the typing of this report is

gratefully acknowledged.

I

iv
TABLE OF CONTENTS

Page

ABSTRACT ill

PREFACE . ........ ................................ ............... ......... iv

LIST OF TABLES ........... vii

1. INTRODUCTION I

1 . 1 Background 1

1 . 2 Purpose and Approach 2

2. CHARACTERISTICS OF PASSIVE SOLAR BUILDINGS 4

2.1 Passive Solar Heating Systems 4

2.2 Passive Solar Cooling Systems 8

3 . BUILDING REGULATIONS 10

3 . 1 Code Enforcement 10

3.2 Passive Solar Retrofit 11

4. HEALTH AND SAFETY CONSIDERATIONS 13

4.1 Indoor Air Qualify 13

4.1.1 Pollutant Sources in Passive Solar Buildings 13

4.1.2 Formaldehyde 14

4.1.3 Radon 16

4.1.4 Rock Storage Beds 17

4.1.5 Building Regulations Related to Indoor Air Quality ...... 17

4.2 Basic Environmental Requirements 18

4.2.1 Ventilation and Illumination 18

4.2.2 Temperature 20

4.2.3 Humidity 23

4.2.4 Noise 26

4.2.5 Weather Tightness 26

4.3 Fire Safety 28

4.3.1 Ignition Sources 29

4.3.2 Ignitability of Materials 31

4.3.3 Spread of Fire 31

4.3.4 Exterior Fire Spread 33

4.3.5 Material Flammability 37

4.3.6 Fire Detection 37

4.3.7 Means of Egress 39

v
TABLE OF CONTENTS (Continued)

Page

4.3.8 Generation and Spread of Products of Combustion 39

4.3.9 Emergency Access 41

4.4 Structural Considerations 41

4.4.1 Loadings 41

4.4.2 Desiccation of Wood 43

4.4.3 Glazing Considerations 45

4.4.4 Summary 51

5. SUMMARY AND RECOMMENDATIONS 52

REFERENCES 55

vi
LIST OF TABLES

Page

Table 4.1 Ventilation Criteria 19

Table 4.2 Illumination Criteria 21

Table 4.3 Criteria for Protection Against Decay and Termites 24

Table 4.4 Criteria for Venting of Attic Spaces 25

Table 4.5 Criteria for Sound Transmission Control 27

Table 4.6 Fire Safety (Clearances from Heated Surfaces) 30

Table 4.7 Fire Safety (Vertical Shafts, Fire Dampers,

Plenums, and Atriums) 32

Table 4.8 Fire Safety (Fire Stopping) 34

Table 4.9 Fire Safety (Material Flammability) 38

Table 4.10 Fire Safety (Means of Egress) 40

Table 4.11 Structural Design Criteria in Codes 42

Table 4.12 Glazing Design Criteria in Codes 46

vii
1
1. INTRODUCTION

1 . 1 BACKGROUND

Passive solar systems make use of the site, form and materials of the building

to collect (or dissipate), store, and distribute solar energy to its occupants.

Energy transfers to and from the building and within the building rely primarily on natural processes, i.e., conduction, convection, and radiation with

minimal dependence on external power and mechanical equipment such as fans and

pumps. Many building components can serve dual functions; i.e., enclosure and

structural stability as well as "capturing" and distributing energy. Passive

heating, cooling, and daylighting, therefore, are intrinsic to the building,

and are affected by its siting, orientation, spatial configuration, circulation, window and door placement, use of building materials and other characteristics. There is considerable information confirming the adequacy of

the technology, cost effectiveness, and thermal comfort provided by passive

solar buildings. This information is resulting in the popularity and growth

of passive solar applications. Such technologies have and will continue to

lead to the development of unique building details and material applications.

However, these applications may introduce new safety and health considerations

within the building environment which are generally not encountered in conventional construction.

Investigation of existing building codes and standards indicates that their

strict enforcement could substantially restrict the application of some common

passive techniques. Although there has been little regulatory resistance to

passive buildings to date, future applications on a larger scale with various

occupancy types will likely face more stringent code enforcement. If regulatory code restraints become a problem, it may be necessary to develop alternative regulations or design solutions in order to ensure that healthy and safe

conditions prevail.

The increased use of passive solar applications includes two somewhat opposite

trends that have significant implications for health and safety of building

occupants. First, as design techniques and the reliability of passive systems

are improving, there is increasing application of these techniques in larger

non-resident ial buildings. This has two implications: (a) in the event of a safety problem, the results could be more extensive and affect more people,

and (b) there is increasing likelihood of regulatory constraints since regulations for such buildings tend to be more restrictive. Like the development

of all building technologies, the successful and safe application of passive

solar techniques relies primarily upon sound building design with particular

attention to construction detail. Competent building design professionals

should be involved in applying the technologies, so the likelihood of any

hazard is reduced.

A second trend, resulting from growing popularity, available guidelines and

apparent simplicity of passive solar design is the increased involvement of

the "do-it-yourselfer." In this case, lack of sufficient knowledge may lead to

potential hazards. There are also problems regarding building code enforcement

1
in such instances since the "do-it-yourselfer" may often circumvent the building

regulatory system by doing work outside the building permit process. According

to Balcomb, "the apparent simplicity of passive solar building has misled many

people into thinking that passive solar design is simple. In fact it is a complex process, a subtle complexity consisting of consciously designing to

take advantage of environmental energies and natural processes" [1]. U

The use of solar energy is generally considered environmentally harmless,

presenting few health concerns. However, applications of technical innovations

could introduce new construction practices which may result in conditions that

are potentially harmful to the health, safety, and welfare of the occupants.

Accordingly, it is important to identify such practices in the initial stages

of their development in order to more consciously control their application

through the design process. An excellent source of technical information for

materials used in solar systems and with an emphasis on environmental and

safety considerations has been completed by Sandia National Laboratories [2].

1.2 PURPOSE AND APPROACH

This research was conducted to identify and understand the nature of health

and safety considerations in passive solar buildings. These considerations

are related to current building regulations applied to such buildings. It is

necessary that health and safety issues be considered to allow for the

technology to continue rapid development.

The study focuses on two aspects of the impact of building regulations:

(1) how they may act as constraints to the effective utilization of the

technology; and (2) how they may not adequately address the new and unusual

health and safety considerations associated with the technology. Generally,

current building codes cover passive solar construction practices which do

not vary greatly from conventional building construction practices. However,

the prescriptive nature of some code requirements often restrict the use of

passive solar technologies which depend upon slight variations to typical

construction practice. Moreover, there is the issue of passive solar applications which result in radical variations from standard construction techniques.

Not specifically covered by existing regulations, these departures depend most

critically upon sound design and construction to ensure safety. This study

addresses these issues and identifies areas in which additional research is

needed to support definitive safety criteria.

The purpose of this report is to present an overview of the current state

of passive solar technology; summarize relevant health and safety issues; discuss the status and impact of regulatory coverage in the model building codes

and other related documents; and to identify and discuss technical issues and

research needs for promoting broader acceptance of the technology. Building

code constraints affecting passive solar which are not health and safety

related are not discussed in this report.

1 / References are listed on page 55.

2
The health and safety topics included are fire safety, indoor air quality,

physical hazards, environmental requirements (e.g., illumination, temperature

control, humidity, noise), and structural safety. The nature of this investigation is general and is intended to relate to most building occupancy types

except those classified as industrial. Residential, small scale commercial

and institutional buildings will be emphasized because most of the passive

solar activity to date has been in this area and this trend is expected to

continue.

The possibilities for redesigning existing buildings to incorporate passive

solar technologies are widespread and have thus far proven to be very successful. The current economic climate has tended to reinforce this kind of solar

application. Therefore, regulatory issues of particular concern to the

retrofitting of existing buildings are also covered.

3
2. CHARACTERISTICS OF PASSIVE SOLAR BUILDINGS

There are five essential components of passive solar systems: Collectors

collect the available energy from the sun. Virtually any material on the

exterior of a building becomes a potential collector when exposed to direct or indirect solar radiation. Glass windows are among the most effective collectors since they admit a large portion of the sun's energy but prevent it from

escaping after it is converted to heat or thermal energy by striking dark

objects. Absorbers are dark colored surfaces or objects such as floors or walls which convert the sun's short wave radiant energy into longer wave thermal energy. Dense materials such as stone, concrete, masonry, and water are

used as absorbers in buildings. Storage is any mass such as masonry floors,

walls, or containers of water which retain the thermal energy collected from

the sun until it can be used (usually when direct solar energy is not available).

Distribution is the means by which thermal energy is moved from the point of

collection or storage to occupied spaces. This is most frequently accomplished

by the natural means of convection, radiation, and conduction using such building elements as walls, openings, and spaces. Ducts, plenums, pipes, and vents

are also often used. The selective use of fans and blowers is sometimes

required. The term hybrid is frequently used to describe systems in which

devices using depletable energy (usually electricity) are used to distribute

solar energy, but this report will consider those as passive. Controls are important to prevent excessive overheating and underheating. Shading devices

such as properly sized roof overhangs, operable vents, movable insulation, and

reflectors are examples of control techniques. Controls are also intrinsically

linked to system design, sizing, relative locations of collection and storage

areas, energy load requirements, and scheduling of energy use.

2.1 PASSIVE SOLAR HEATING SYSTEMS

Passive heating systems are solar systems in which the building structure is

designed to collect the sun's energy, store the energy, and distribute the

resulting heat by natural means. Specific systems which utilize these concepts

are discussed below.

Sun-Tempered Buildings can be considered

as conventional with special attention given

to orientation and south-facing windows.

4
GENERIC PASSIVE TYPES O

Direct Gain Is the most common and simplest

passive solar concept and usually differs

from sun tempering by the provision for substantial storage mass as part of the interior

living spaces adjacent to increased southfacing windows or other glazed openings.

Direct Gain

Storage Wall (indirect gain . . . Trombe

wall) is a passive technique in which

storage mass is positioned immediately

behind south-facing glazing and separates the glazed solar energy collection

area from occupied spaces. Although

this is an unusual building feature,

it is normally constructed of conventional building materials and methods.

Vented Trombe

5
Sunspace (isolated gain ... greenhouse,

solarium) collects and stores solar

energy in a secondary space separate

from but thermally linked to adjacent

occupied spaces.

Sunspace With Direct Gain Wall

The Storage Roof (roof pond) concept is

considered a special case of Indirect

Gain with very large bags of water on

the building roof providing storage

mass. The roof construction, supporting structural system, and heavy-duty

movable insulation over the water bags are the most unusual characteristics

of this system.

Storage Roof

6
Solar Attic

Double Envelope

° SPECIAL TYPES

Solar Attics may be considered a special case of Sunspace. The southfacing portion of the roof is glazed

and acts as a collector. The attic

floor (and perhaps walls) are dark

colored and act as absorbers. Storage

may or may not be provided on the attic

floor or adjacent walls.

The Double Envelope is unique although

the solar energy collection is usually

similar to the Isolated Gain or Sunspace type. The concept of circulating

a stream of solar warmed air through

double wall and attic spaces requires

unusual construction methods for structural framing and sheathing.

Earth Contact Buildings vary from

below ground structures to those

having earth berms covering major

portions of one or more exterior

walls of a building. These buildings

may have other passive features but

they are distinguished primarily by

the fact that they are at least

partially below finished grade.

7
2.2 PASSIVE SOLAR COOLING SYSTEMS

Passively cooled buildings are designed to minimize summer daytime heat gain

and to utilize nighttime coolness and the cool night sky for heat loss. Properly

placed windows provide for the circulation of cool air removing the heat which

has accumulated in the storage materials during the day. Overhanging eaves to

shade windows, insulated windows and shutters, and selective location of shade

trees all contribute to keeping the building cool. Specific systems which

utilize these concepts are discussed below.

Induced Ventilation . A "thermal

chimney" effect is created by solar

heating in a restricted area, which

facilitates the rise and external

venting of hot air. Replacement

air is drawn from adjacent occupied

spaces which in turn is replaced by

air taken from cooler outdoor

sources

.

Induced Ventilation

Night Sky Radiation

Night Sky Radiation . Cooling is

achieved by exposing a massive body

of water, masonry, or possibly metal

to the cool night sky. During the

day, the mass acts as "cold storage"

that can absorb heat from the interior

occupied spaces. The storage roof and

storage wall techniques discussed earlier are common approaches to night

sky radiation. Solar attics may also

be adapted for this purpose.

8
Evaporative Cooling

Evaporative Cooling . A source of

water or a body of water is required

which can be evaporated to decrease

the sensible temperature.

Dessicant Cooling

Dessicant Cooling . This technique

increases cooling comfort by the drying of very humid air which enhances

the natural cooling effect of sweat

evaporation. The use of dessicant

salts (which can be dried by solar),

induced ventilation (as described

earlier as the thermal chimney effect),

or some dehumidifiers will provide

dessicant cooling.

Earth Contact . Building below grade

to take advantage of cool and relatively stable earth temperatures, as discussed earlier, is one form of

cooling by earth contact. "Cool

tubes" which extend underground well

beyond the building periphery and use

the relatively low earth temperature

to cool fresh air, is another type.

Earth Contact

This is not intended to be a thorough analysis of passive solar techniques.

It is to be noted that there can be infinite variations of materials and methods

used in applying existing passive solar technology. For a more complete analysis

including typical sample projects, see references [3,4].

9
3. BUILDINGS REGULATIONS

3.1 CODE ENFORCEMENT

Building codes exist in most of the incorporated jurisdictions in the U.S.

and exert control over how buildings are designed, built, and constructed.

The purpose of building codes is to set forth rules to ensure that the building design protects the health, safety, and welfare of its occupants. Model

building codes [5, 6, 7, 8] are in widespread use as the basis for most legal

codes. Individual jurisdictions often adopt one of the models as their legal

code; but frequently the models are amended, so diversity still exists.

Many states have enacted statewide building code programs in recent years, but

unless the state code is totally preemptive and mandatory, most legal codes are

the laws of cities and towns, and each one has the potential to be, and often

is unique [9]. Local jurisdictions may also adopt special standards and criteria as guidelines such as those related to fire safety, energy conservation,

or even solar energy applications. This cumbersome diversity of codes, tends

to impede innovation and efficiency and is further compounded by variations

in interpretations and enforcement by local officials. While progress has

been made in developing uniformity between codes and code provisions and their

enforcement, the multiplicity of codes, lack of codes, lack of uniformity, the

enforcement procedures, their specificity as regards acceptable materials and

methods of construction, and the ponderous amendment procedures, all work to

restrict innovation. Unlike most regulatory processes which define prohibited

practices, the building code defines acceptable practices, hence it restricts

options [10]. Most of the technical provisions included within codes come directly or indirectly from hundreds of national standards that deal with

engineering practices, material specifications, and test methods.

It is reasonable to expect that the incorporation of passive solar systems

into buildings should not create a built environment which is more hazardous or unhealthful to the occupants than that of a conventional building. Requiring

minimum health and safety standards are clearly the major concerns of building

codes. However, strict interpretation and enforcement of the existing language

of many present building codes and standards with regard to health and safety

issues could substantially restrict the application of certain passive solar

technologies.

There have been few reported incidents of restrictive code enforcement applied

to passive solar construction. The more frequent response is one of confusion

and an indication that building officials do not understand passive solar systems and that guidelines are needed. An attempt has been made to provide such

guidelines and this has resulted in, "Recommended Requirements to Code

Officials for Solar Heating, Cooling and Hot Water Systems" [11]. This document was developed for the Department of Energy by the Council of American

Building Officials (CABO) and provides an excellent commentary on some of the

more significant safety problems of passive solar construction. The document

primarily addresses active solar energy systems with the assumption that

current building codes adequately cover the concerns of passive solar techniques. However, passive technology continues to develop, adding new concerns

to those that have not been fully resolved.

10
It has been reported that building officials tend to be lenient with regard to

questionable passive techniques and exercise a willingness to "go along in the

interest of energy conservation * " Such leniency cannot always be anticipated

from one jurisdiction to another. For building permit purposes , one code

official suggested that perhaps buildings should not be promoted as "passive."

This supports the idea that the regulation of passive solar construction should

be no more and no less vigorous than for conventional construction.

As will be discussed later, some characteristics of passive solar systems may

exceed regulatory minimuras while some techniques could present potential hazards. This situation provides opportunities and justification for applying

alternate solutions based on equivalent performance. Each of the model building codes provides for the building official to approve alternate materials

and methods and to exercise judgment where some features are not specifically

covered. These provisions also mandate that the building official shall

require sufficient evidence to justify alternative methods. Although this

provides a means for the approval of alternative techniques, it places the

burden of proof on the designer which could be considerable. The building

official who is unfamiliar with passive solar is also at a disadvantage and

may be reluctant to make judgments without a firm technical basis. He would

prefer to have prescriptive standards to follow. For these reasons, it is

necessary to develop sound regulatory requirements and supporting technical

guidelines which allow continued development of the technology through

system design innovation, but also provide a sound base from which subsequent

evaluation for code compliance can occur.

3.2 PASSIVE SOLAR RETROFIT

The nature of current regulations as applied to existing buildings can have a significant impact on the solar retrofit [12]. In general, building codes

address the following categories of building rehabilitation: (1) additions to

existing buildings; (2) maintenance, alteration, and repair of buildings not

Involving a change of use or occupancy; and (3) maintenance, alteration, and

repair of buildings involving a change of use or occupancy. Rehabilitation

Guidelines [13] published by the Department of Housing and Urban Development

provides detailed analysis of code coverage for existing buildings.

The model building codes generally require that the entire building comply with

the new construction requirements for the new occupancy when a change-in-use is

involved. When no change of occupancy is involved, most building codes contain

provisions, variously worded, requiring that a building's conformance with the

requirements of a currently enforced building code for new construction should

increase in relation to the dollar amount of the rehabilitation planned. This

mechanism for triggering compliance with new construction codes is known as the "25-50 percent rule" and is contained in the following sections of the

model building codes: Basic Building Code [5] - Section 106.0 (1978 Edition);

National Building Code [6] - Section 104.3 (1976 Edition); Standard Building

Code [7] - Section 101.4 (1979 Edition); and Uniform Building Code [8] - Section 104 (1976 Edition).

11
The application of these administrative provisions is based on the following

general economic hierarchy:

1. The entire building must comply with the building code for new construction when alterations exceed 50 percent of the building’s

value

,

2. The extent of conformance of the building altered to new construction

requirements is up to the discretion of the building official when

the cost is between 25-50 percent of the building's value, or

3. The alteration must be restored to at least its original condition

for an alteration which costs less than 25 percent of the value of

the building.

There are serious economic implications in applying these buiding code

provisions when solar retrofitting an existing building. Costs of modifications could trigger the "25-50 percent rule" and require compliance with the

code for new construction. For example, if the cost of the solar retrofit

exceeded 50 percent of the value of the building (assuming use and occupancy

remain unchanged), then other building systems must be upgraded even though

they would be unaffected by the retrofit. This may cause the planned retrofit

to be unfeasible from an economic viewpoint.

Recognizing this potential constraint to the broad acceptance of solar energy

applications in buildings, the previously referenced document [11] addresses

this issue in the following section:

"G-101.5 Existing Buildings

Solar energy systems may be installed in, on, or adjacent to existing

buildings or appurtenant structures without having the entire building

or structure comply as required for new construction, provided the added

solar energy systems and the affected portions of the existing building,

mechanical, plumbing, and electrical systems comply with the applicable

provisions of these recommended requirements."

12
4. HEALTH AND SAFETY CONSIDERATIONS

Passive solar buildings may, in general, be as safe or safer than their

conventional non-solar counterparts while having equal or greater comfort

characteristics. There have been few reported incidents of health or safety

related problems in passive solar buildings. The few known problems have been

relatively minor or have been alleviated before actual harm occurred. Much of

the discussion which follows relates to applications of building materials and

systems and how they are affected by unique environmental conditions found in

solar passive buildings. This discussion is related to current building

regulations which control the design of such buildings.

4.1 INDOOR AIR QUALITY

The probabilities of a buildup of indoor air pollutants due to characteristics

of passive solar buildings have not been precisely determined, and the level

of hazard they present is uncertain. There is, however, a large and growing

concern for this potential health problem. A Department of Energy study [14]

concluded that "the major environmental research problem associated with passive solar heating and cooling is indoor air quality." This concern results

primarily from the energy conserving trend of greatly reducing air infiltration

in buildings. This is an important conservation practice, one shared by passive techniques, because air infiltration may account for 50 percent or more

of the heat load of a building. When this practice is combined with certain

materials and techniques used in passively collecting, storing, and distributing

solar energy, concerns may arise.

Reduced air infiltration results in higher concentrations of various pollutants

emanating from interior sources and, therefore, a potential health problem. A

recent article in the Journal of the American Medical Association (AMA) states,

"The combination of hazardous materials in a tight structure simply allows these

materials to build up rather than dilute" [15]. As reported in the April 1981

American Society of Heating, Refrigerating, and Air Conditioning Engineers

(ASHRAE) Journal [16], the National Commission on Air Quality in issuing the

final report of a three-year study of the Clean Air Act, addressing indoor air

pollution for the first time. The same article cites a preliminary finding of a DoE study of houses in Oregon indicating that control of the pollution sources within a house may be preferable to eliminating the pollution through ventilation. Passive solar not only promotes this "tight" building concept but also

may inadvertently increase the sources and incidence of indoor pollution.

4.1.1 Pollutant Sources in Passive Solar Buildings

Some of the pollutants and sources that are of concern especially in passive

solar construction include:

Formaldehyde and other toxic outgassing products - plywood, particle

board and foam insulation (also furniture and carpeting).

13
Radon - mass storage components, masonry floors and walls, rock beds,

earth storage (envelope construction), earth contact (underground and

bermed earth).

Bacteria, fungus growth, dust - rock beds or other remote storage

media, earth storage (heating and cooling systems), cool tubes.

° Pesticides and other chemical treatments - solar greenhouses,

crawlspaces, earth storage (double envelope construction), earth tubes.

In addition to the above sources, there are other interior environmental

conditions prevalent in passive buildings that further aggravate the indoor

air quality problem.

° Elevated temperatures at the point of collection/absorption of solar

energy. This increases the emission of formaldehyde from plywood,

particle board, urea-formaldehyde foams and furnishings including some carpets [17]. This effect is significant at moderate temperature

levels, 27°C (80°F) to 32°C (90°F). Much higher temperatures,

93°C (200°F) to 150°C (300°F) (which may occur during stagnation) can

result in outgassing of other materials including other types of

insulation.

° Increased humidity also increases the emission of volatiles, especially

formaldehyde [17]. High humidity also increases the potential for

condensation and, therefore, mold, mildew, and fungus growth.

° Passage of the air stream through the structure of buildings (wall

chases, attic, and crawlspaces), through the ground, and storage bins

exposes building occupants to more pollutants, especially particulates.

° Reduced-air infiltration has been identified as elevating the

concentration of indoor pollution, through this alone does not usually

cause much of a problem unless sources of pollution are large.

° Miscellaneous contributors to the problem of indoor air quality may

not be unique to passive solar but should be mentioned. The use of

wood burning stoves, which are frequently used as backup sources of

heat, may add a significant amount of pollution to the indoor air.

Another concern that has been recently expressed is for the synergistic effect of pollutants combining either in or outside of the body

to produce even more toxic substances. This would involve cleaning

fluids and a whole host of chemicals and products that are now common

in most buildings.

4.1.2 Formaldehyde

Formaldehyde is one of the most prominent of the indoor air contaminants. It

is most commonly associated with urea-formaldehyde foam insulation which has

been the subject of a major regulatory controversy. This material has been

banned in some states including Massachusetts and the U.S. Consumer Product

14
Safety Commission has taken action to ban the material completely effective

June 1982. Other major sources include: (1) particleboard, used for underlayraent, cabinets, furniture and paneling; (2) plywood paneling, especially hardwood plywood^; (3) a variety of carpet types; and (4) resin-treated upholstery.

Significant levels of indoor formaldehyde may also result from tobacco smoking

and from poorly vented gas appliances.

The major source of formaldehyde in building materials is urea-formaldehyde

resin which is used as an adhesive in wood products, and as a finishing agent

in textiles. Formaldehyde is released from the gas trapped in the product and

from the hydrolytic decomposition of the resin polymer. Formaldehyde emissions

decrease as the volatllizable gas is released and the product ages. Continued

low-level long-term formaldehyde emissions will continue, however, as the ureaformaldehyde polymer undergoes hydrolytic decomposition. Because of this, as stated by researchers at Ball State University [18]. "...formaldehyde exposures and building-related illness may continue for years." The health effects

include: eye and skin irritation, upper respiratory problems, headaches,

dizziness, nausea, and fainting. Based on animal experiments, it is suspected

of causing nasal passage cancer. Of great concern is the suspicion that

formaldehyde may lead to the development of asthma, or to complications of

asthmatic conditions. The dose-response relationship for the occupationally

exposed adult has been identified [19]

.

Much of the data pertaining to formaldehyde release and occupant illness comes

from investigations of mobile homes. One such study of 334 mobile homes

reported formaldehyde concentrations ranging from 1.77 ppm to a low of 0.03 ppm.

A number of conventional houses and buildings, including offices and schools,

have also had concentration levels resulting in illnesses. Many studies suggest a combination of "tightness” or low air infiltration and a substantial

amount of formaldehyde releasing material is necessary before problems occur. Unless strong sources of formaldehyde are present in a home, energy-conserving

measures aimed at "tightening up" houses should not lead to problems of indoor

air quality due to formaldehyde [20]

.

Passive solar buildings which experience periodic elevation in temperature and

humidity may increase the emission of formaldehyde from affected materials.

An elevation of relative humidity from 30-60 percent at a given temperature

will result in roughly a doubling of formaldehyde emissions [17]. Conditions

in direct gain systems could lead to significantly elevated temperatures in

carpets, upholstery and paneling. Particleboard, plywood and other materials

used for the surfaces of solar attics or air collectors may reach temperature

levels which would increase formaldehyde emission from these materials, causing

them to be circulated into the air stream. Because of their potential for

elevated humidity, attached solar greenhouses and earth contact buildings,

including the use of the earth or crawl spaces as a heat sink, may produce

problems, if materials containing formaldehyde are present.

It should be noted that phenol-formaldehyde resin, primarily used in

exterior grade plywoods, is much more stable that urea-formaldehyde,

therefore resulting in only a fraction of the emission of formaldehyde.

15
4.1.3 Radon

Radon is a substance known to be carcinogenic to humans at elevated levels.

At lower levels its carcinogenic effect is unknown but strongly suspected.

It is found primarily in the soil and ground water but it is also present in some masonry building materials. Fortunately, the presence of radon and its

progeny at significantly high levels, is site specific. Its concentration

in rocks and soils varies with location and, likewise, building products

produced in various locations vary in radon concentration. Radon itself is

inert and, therefore, not a primary health hazard. However, its presence and

concentration is an indicator of the exposure to the biologically important

radon decay products. Radon decays into four decay products which are alpha

emitters. These decay products become airborne attaching themselves to particulates. If inhaled, they can enter the respiratory system and become

lodged there. The primary health hazard is due to alpha particle emission of

polonium-218 and -214. Alpha particles have a very short range and essentially

all of the energy affects are near the surface of the lung. Continued exposure

allows concentrated alpha particle emission in a relatively small area, causing

serious effects.

Building materials which contain radon are granite, concrete blocks, earth

masonry units, bricks, tile, and gypsum boards [21]. The variation of radon

contents in similar materials may be very large. Other sources include soil,

ground water, and natural gas. The indoor exposure levels from these sources can be significantly higher than outdoor levels [22] . This is dependent on location and building ventilation rates. The resulting health impact is

enhanced risk of lung and other cancers [23]

.

The Swedish National Institute for Radiation Safety estimates that 1 pCi/L

limit of radon corresponds to a cancer risk of 20-200 cases per million [24]

.

The maximum permissible concentration (MPC) for airborne radon concentrations

recommended by the Health Physics Division of Oak Ridge National Laboratory

should not exceed 3 pCi/L. Some radon concentrations inside of buildings in

the U.S. and various foreign countries are reported in the literature and they

greatly exceed these recommended permissible levels [23]. Dr. Tom Hess of the

University of Maine reports radon measurements levels of up to 200 pCi/L in

some houses in the state. These houses were built in an area with outcroppings of granite and contained solar energy storage beds of crushed gravel.

The importance of the rate of ventilation and air tightness of buildings on radon concentration is demonstrated by recent investigations at the National

Bureau of Standards (NBS) [25]. Relatively high concentrations of 8 to 18 pCi/L were measured in preliminary investigations of six thermal mass test buildings

tested in the spring of the year. Tests conducted in the same buildings later

in the fall showed that the air infiltration rate doubled along with the radon

emanation rates. Measurements were similar in all six buildings although they

vary in construction and materials from wood frame with wood siding to solid

masonry walls. All six buildings have slabs on grade. Radon concentrations

seem to be fairly well correlated with the air tightness of the buildings and

not the type of construction. The buildings are extremely well sealed with the

highest air leakage rate measured at 0.09 ACH (air changes per hour). The

buildings were rarely opened except for test purposes.

16
4.1.4 Rock Storage Beds

Rock beds are commonly used for thermal energy storage in both active and

passive solar systems. More typical for passive or hybrid systems, the rock

beds are within the foundations and in contact with the floor slab above.

This tends to make them inaccessable for monitoring or correcting any problems

that might occur within them. There have been few reports of serious health

problems associated with rock bed storage. There have been some problems with

dust and odors. Warm rock beds have evaporated the water seal in the trap of

drains of rock boxes permitting sewer gases to enter the air stream. In other

cases, odors are suspected of being caused by mildew or fungus growth in the

rock bed. Mildew is harmful to many materials but any specific health effects

are not readily determined. It is, however, a strong indicator of the potential

presence of other fungus and bacteria which may have health concerns.

Washing the rocks prior to installation can help eliminate dust and other

impurities. Equal care in specifying the source of the rock will aid in avoiding hazardous materials such as those containing asbestos particles or radon

gas. The unique hazard potential is created when passing the ventilating air

stream through an uncertain and inaccessable medium.

4.1.5 Building Regulations Related to Indoor Air Quality

The model building codes address indoor air quality only in very general terms.

Ventilation, however, is addressed in very specific terms and frequently in the

the form of prescriptive requirements. The intent, as stated in the Minimum

Property Standards of the U.S. Department of Housing and Urban Development [26].

"is to provide light and ventilation to achieve a healthful environment within

the dwelling and so located as to provide an acceptable degree of comfort."

Illumination and ventilation requirements are discussed in section 4.2.1 of

this report including a tabular presentation of pertinent code provisions in

the model building codes and related documents.

Designers and code officials alike have not fully anticipated the health

problems that might be created by "tight" energy conserving buildings. Some

codes require mechanical ventilation ... "when rooms, which by use or occupancy,

involve the presence of dust, fumes, gases, vapors or other noxious or deleterious impurities that create a fire or health hazard" ... The provision further

requires that, "ventilating systems shall be kept in operation at all times

during normal occupancy of the building or space so used." This provision was likely written without the anticipation that building materials and furnishings

might produce noxious or deleterious impurities under some conditions. The

NFPA Life Safety Code [27] does point out that features such as exposed insulation may establish a significant "Hazard of Content Level." This provision

might have direct implications for many movable insulation techniques in

passive solar, although there is no evidence of such an interpretation and

enforcement of these provisions.

The CABO document [11] addresses solar applications even more directly by

requiring filters at the outlet of rock storage beds when air is forced through

the rocks and into habitable spaces. This requirement may significantly

17
restrain those hybrid techniques which operate at a very low pressure drop as well as for systems which reverse air flow from rock beds for heating (or cooling) from storage. Required ventilation rates or requirements for operable

windows, discussed more fully in section 4.2.1, will also restrain some passive

strategies

.

ASHR.AE Standard 62-81 [28] provides for a safe, healthful, and comfortable

indoor environment by using materials and methods which optimize efficiency of

energy utilization. It specifies acceptable levels of certain contaminants in

the air within buildings and sets the minimum rates of ventilation necessary

for human comfort. Such contaminants may be present in makeup air or be introduced from indoor activities, furnishings, building materials, surface coatings,

and air handling and air treatment components.

4.2 BASIC ENVIRONMENTAL REQUIREMENTS

This section discusses the issues of ventilation, illumination, temperature,

humidity, and noise as related to passive solar design. It also includes a discussion of general considerations of health and sanitation sometimes referred

to as environmental requirements — room sizes and proportions, odor, rodents

and vermin are examples. The health and safety effects of some of these issues are subtle; however, there is a broad agreement for most of the building

regulations covering them.

4.2.1 Ventilation and Illumination

Ventilation is one of the most significant environmental and energy conservation

issues. Table 4.1 summarizes ventilation requirements in the model building

codes. Air movement as a means of achieving cooling is a common passive technique. The primary health concern Is that the source of ventilating air be of

acceptable quality, as was discussed in section 4.1, Indoor Air Quality. A

second concern is for those cases where ventilation is greatly reduced in the

interest of energy conservation with a detrimental effect on the quality of

indoor air. A passive technique that is becoming increasingly popular is the

collection of solar energy and the distribution of warm air through common

building spaces such as atriums, corridors, stairways, etc. Most codes prohibit the circulation of supply/return air through multiple occupancies

because of concerns for the spread of fire and smoke and potential sanitation

problems. Some recent code changes contain specific requirements for atriums

for fire and smoke protection (discussed under section 4.3, Fire Safety).

Minimum requirements for natural light and ventilation in building regulations

are presented as a percentage of floor area. It is not clear how this ratio

relates to specific health issues. This constant ratio could limit passive

systems which tend to optimize the use of natural light, and ventilation. Also,

many passive solar designs for residential buildings call for minimizing exterior glazing on the east, west, and north exposures of buildings. Such designs

directly conflict with the current code provisions requiring minimum glazing

areas for natural light and minimum openable areas for natural ventilation in

habitable rooms. These code provisions could inhibit the use of solar

18
Table

4.1

Ventilation

Criteria 1 1 60d AJ 1 •H CO 1d i e d •H CO 1 o (LI CO tH H i d X

d

Ci tH ] > 3 AJ c Ui

X

d *H (U Q1 0) tH Aj 4h CJ

d

C/5 ai •H 1 ai Aj c Aj 4) 4!

d

d

O ai AJ Oh 2 tH

V tH

d 01 o 01

H AJ AJ <D CO o 0 0) • 01 -2

Md

d CO *3 X. 60 J3 s X AJ 0 CO

D crf tHd >- 3 u 0 CO COOO aj

d AJ

d c 4-1 CO

O CJ

d o H 3 d

<c 3 d ai e ai

X o 4H

U aj 0 0 •H 0 0 60 Aj AJ 3 d •H Ai j > 3 <u 3 0 CO •H 01 AJ 0 o 3 •» o e Oh CO •H d O c 5 o 01 cr o> CJ 0) a 60 4H 4-1 d Aj d 0) •H •H jQ CO 01 AJ 4-1 0 M C/5 pH *—i • a) aj N o c CO 3 0 c OJ tH tH u 3 tH X d 01 tH Aj H \ X d CO Vj d Cl d d AJ ai •H AJ 2 0 AJ > a, H 3 rH d AJ J3 X 01 2 AJ CO w d Aj d CO i—<

01

a

a •Hu > • d o *H

d (LI Aj CO »H o d

a o d 2 > u 3 o d aj 60 JSZ CO 3 e 4) l-i Ai 0) 3 AJ 4) 2 o d o 3 AJ 60 U CJ AJ tH pH o M a. aj •H 0 o aj d CJ •H 3 0) d s d d CO O AJ 0 a, X a c O CU AJ tH •H • M C/5 ai d CO •H •tH A o 3 CJ rH •H CO p—i

•H tH oj 31 *H

X 0) •H 4-J 01 01

d AJ 01

H 00 0 d •H AJ VJ CO CO o CO

d o Vj 2 •H CO Aj 01 Ai AJ

X CJ

X 3 > < <c cj > d u e u.J

a) c 0 CO •H AJa a)

a

d 0 4-1

d

H CJ AJ CO 01

H o Oh d o o pH CO 3 o CO 0) 60 o a 3 ai a • 60 d tH a CO O d 01 > AJ

t—1

AJ aj 3 01 •H

d r—1 d o 01 cr 01 o s d CO At o •H •H

d 3 d

-J z COa

a Vj CO

ad >6 > ai

X > AJ cu AJ 2 0) CO ai AJ CO • d *H o tH

d o 2 01 Vj AJ Vj CO •h j= 4) 60 •H u d tH d o X AJ d •H CO d CJ d Aj c > d •H AJ d o d AJ CJ CO Vj CO u tH 0 XI d 3 AJ cu d CO > g 01 CJ 01 tH H •H o o d *3 ai i—( u o ai CO cu <u d 01 O > fl 3 > cu o o 2 > CJ H AJ r—1

AJ •h 0) a) 4-1 •H Aj 3 •H

Xd

d

X Oh

U cu Aj 3 •H

O *H Aj

d Aj 0 O •H

X 3 tH <C d aj a o Aj d 0 c AJ 0) a H o 3 CO Oh d 2 CO CO CJ H a u tH AJ AJ d d

AJ 4j lJ tH pHd £ 60 •H vH d d CO 0) X tH 01 01 V c d d o Aj d > Aj AJ * ai d • Ax 3 pH

AJ •H •H 01 •H 01 1 o 3 o d Aj i 01

d

d XI

CO

d c 4-1 AJ

dd AJ • AJ 01 4-J

H

X 01 01 *Hd Aj

N

d

•H •H o o d 01 60

O

d 2 d Ai 0 Aj 3 •H AJ 01 tH Aj CO 3

CO 4-1 •H 3 H 60

d •H

d o Aj 01 01

d

d cr 3 4-i CO 01 01 01

d CJ AJ COd 3 •H AJ Aj 3 60 3 CO 11 Aj CO (U 2 X 4-1 rH AJ CL

O 3 d 0 d CJ CO 2 d ai 3 01 o o U

d 01 Aj o •H AJ rH

d o 2 a •H C Aj •H o pH AJ *H AJ •H JC 3 ai rH 3 3 u d pH o d 3 •H 01 Aj •H tH *H rH 2 3 AJ AJ *H >> X X CO d CO d 0 3 0 H •H •H AJ AJ 3 CJ 01 rH AJ d •H d CO 01 AJ d 01 •H 01 Ai X CO a 3

C/5d

O Aj

d 3 01 rHX

X

d 3 £ CJ

O 4) iH e

C/5 0) 01 01

d

X Aj 01 01 ai tH CO *H AJ AJ AJ 4-1 01

O

d 3 d AJ *H 3 Aj AJ > •H *H X d > rH X 0) AJ •H X O Q, CJ 01 CU *H 01 CO 0

CJ

d 01 Ajd

H o jQ

d 3 3 2 60

A

O

d CO 0 X CO •H

C/5 rH rH CO ai tH

d Vj

O 01

H CO

d 01 o AJ 2 o e

HH CO CU

d ai cx u-l AJd AJ 01 CJ > AJ rH 0) o Aj

X 0) 01 o CO

a ai 0 CJ •H o * d CJa (X

d CO •H

O AJ AJ pH Aj 3 tH CJ 01 3 o •rH AJ CO 3 01 •rH 01 o 01 tH ai rH d AJ CO J3 d •H rH H AJ

01 s: aj H o H <U AJ u 50 C d d 3

eg

d o 3 JC B

cr cj aj

ai

ad £ ai d O 01 J= i o H 00 Q) d d a oo a d d d o d AJ

a

d o

01Vi Aj3 4J 3 Cd u4 d o 5 2 ° 3 3 4h d

•H

cd 15

u-t cd O 01

«a;

d

d -d

XT AJ

<D CO

l-i (1) a> od

0)

d 3

<D rH • < rH O d

CJ *H CO 01 O -d -d J-l « 3 d d

m o o Aj AJ 1 00 1 o d O CO 3 d 1 d •rH AJ *H O 4-1 3 •H p o r—1

tH 3 d

p tH o 0 2

CO Aj •H i—1

Aj

O 3 AJ Aj Aj 4-J rH vy 3 AJ d 3 Aj 4-J o d 3 3 • • d 01 pH H O AJ d X O •H CJ ai AJ O Aj 4-1 3 o tH d 2 X CL rH X d >% rH d X •H O *H X) a 01 3 3 AJ tH d 3 d X-N s1

AJ

d

d s Aj CJ CJ o Aj X *H 3 > Aj • Vj d d tH w 01 X Aj 0 01 CO AJ 4-J Aj ai 4H AJ •H d d d pH cu

erf CL 01 •H 0 CL 01 3 SI 3 O CLO 4-Jd 01 01 01 tH CL AJ

M

a o Aj AJ V? 4-1 Aj Aj CM Aj AJO

X

3) CO

d 01 CJ CO

d 4J 3 tH 01 CO

d • X

dd AJd 3 60 O' 01 o crf 01 o cr d • CO • 01 o cr CO 4-1 01 •H

CD 60 tH J3 60 *H ai 01 • AJ

d 60 •H CO 01 Aj Aj Aj > pH rH

Crf

d AJ 60 • d AJ 3 AJ -d • 3 o d AJ Aj

OO

m

O *H

d

d • 3 ud

d •H 3 • 01 •H

d

d Vj 4-J

OOO 4j CO CJ X H CO O AJ X *H > d) 3 H AJ X «H 01 rH pH tH o d CO H CJ 3 d Aj ai CJ 3 O tH •H 01 d CJ 3 CL 4j 4-1 Csl 4-1 ai CO CJ 01 -d CJ Aj O d • Aj rH CJ X-N 0 01 Aj • Aj Aj -d AJ p Aj Vj CL •H AJ CO *d •H Aj Aj 01 5^ • 4H 4-1 4-1 CJ d O CO CQ •H •H CJ CO •H •H • 4-J d 3 3 AJ *H •H 0 VAj d O o vO O Aj d 01 d CJ AJ AJ d CJ • 4-J •H o cr d d CJ d O ai 3 2 CO

0) *H o d ai • 3 d *H 01 ai 01 CO Aj • o 01 o d

Csl Aj

d 2 CM Aj • CO 0 AJ Aj > LO Aj v-r CM

dm

O in CO X) 3 a

pH o CO • CO CO • 01 01 0) x>

iH 3 r—1 3 CO o

CD

O

m o o in

O

u CJ CJ 2 p

p

CD 60 o m 60

m 60 pH

Crf 3 • • 3 v£> • 3 • CD •H <r m *—i

*H • m *H cn

m

Cu 3 o o o 3 CM o o 3 O o CD rH m CM o >H pH CM o rH m CM

Crf •H P pH

p CM •H in *• pH * CM •H * pH 3 CO 3 3 CO CD « m 3 00 3 n d CQ m d 00 3 r-t d CQ m 3 oo 3 Q i—

o •— o —• O i i o — o t—* o i—j o ^ o i—i o tH •H tH *H tH tH •H tH tH

CJ ai c AJ

O AJ CJ AJ 01 < AJ

C AJ

u 0) < AJ

O AJ o 3 o a CQ o o o 3 CJ a CQ CJ CJ) o 3 o O « o O O O 01 CJ 01 CQ 01 O o 0) CJ 01 CQ 01 O o 0) a 4> CQ 2 « CO M CO CO CO s CQ CO H CO CO CO s CQ CO M CO CO 1d 1d

r—1

crf •H •H x—\ 1 CD AJ 01 AJ CO d H 3 r—1 d 0 >H H 0) x> 0) o tH > d > o AJ

AJ Aj 3

rH tH tH

X 01

H

CJ

CD3

CQ

C/5

d X5

cj

d

•H SI dd

-dd o o

QJ *H

23

u

d aj o d

*H -O d v-/

19 1/

References

are

listed

beginning

on

page

55.
greenhouses in both new construction and retrofit situations if windows

providing natural ventilation are no longer facing outdoors.

Illumination of habitable spaces is an environmental requirement of most

building regulations. Natural light is generally required of all habitable

and occupiable spaces as shown in table 4.2 although the safety and health

implications are not clear. The use of windows for emergency egress and/or

ventilation are given primary consideration. For some types of passive buildings, natural light is greatly reduced or even eliminated for northfacing rooms

to decrease the heat loss attributed to windows. Underground or earth contact

buildings sometimes have difficulty meeting these standards except for southfacing rooms where windows are concentrated. However, many earth contact

buildings resolve this concern very adequately by orienting a large majority

of habitable rooms to the south, providing atriums, light wells, skylights,

and clearstory lighting.

The use of natural light to reduce the energy used for artificial lighting is

a very important facet of passive solar systems when applied to many commercial

buildings. Lighting often accounts for more than 50 percent of a commercial

building’s energy load, and it also increases cooling requirements.

Glare is another problem with health and safety implications that can result

from the improper design of daylighting systems (as well as passive space

heating techniques). The combination of large windows, reflector enhancement,

and hard, dense surface areas can create substantial glare problems. Glare

most often results from a bright light source with a contrasting low level of

illumination. Glare can cause temporary impairment of vision and eye related

discomfort. It was one of few "minor" problems reported in follow-up interviews in a recent survey of purchasers of passive houses in the residential

solar demonstration program [29] . Proper and careful design of daylighting

systems can eliminate the problem of glare altogether.

4.2.2 Temperature

Significant temperature fluctuations can result from improperly designed and

controlled passive solar systems. Overheating or rapid heat loss from habitable spaces can occur if there is a poorly designed relationship between aperture, storage or building mass, venting and shading devices or other control

techniques. For example, if there is an improper balance between collector

area and surface area of the storage mass, excessive surface temperatures can

result. Specifically, this can occur when relatively dark, high density materials, that might be used for flooring, are directly irradiated by the sun for

substantial time periods. If resulting ambient and radiant temperature fluctuations are not properly matched to occupant comfort requirements (relative to

age, health, and schedule/type of activity), health problems could result.

Moderate temperature variations can be tolerated or compensated for by healthy,

young adults. Infants, the elderly and the infirm may be more susceptible to

these conditions with respect to discomfort and possibly health effects, although

there is little medical evidence to support this. Health effects may become

of greater concern relative to the various age, health, and activity groups as temperature fluctuations increase. The rate of temperature change and the

20
Table

4.2

Illumination

Criteria

XJ

XJ o d d d •H i CO a) c0 2 TO c H e >% M a 0) X O Dd 3 cO M M 3 c M e CLI 00 3 <M

a,X •H

O

d 4-1 XJ o § o 3 XJ •H °H 3 M CO o' x M XJ XJ O cu 3 60 O X co X o

co

w

u •M 4-1 60X XJ

M • z > rH •H 3 •rH 3 4J o l-l 3 XJ rH CO 3 O X

hH CO T3 rH rH C/D 60 H co o cO 3 rH 3 CO •H

<? <; CJ

M CJ coX cu cO rH

cj CU 3 •M •H o

«—1

oo XJ 4-J e o o CO co rH

J z d cd <M co •H XJ

a cO cO

p_< o •H

d •rH CD <M CO

M § U 33 cj *H cu CA 3 M V !-i cd XJ > M 3 XJ V O 3 a u cO o o co s CM X C/D < X 4-1 33 d

c/d XJ 1 3 & M d cu d <U rH o O 3 XI rH cu 63 a>

u

X T3 •H e H c0 > OX o

CO

d

M

V

u rH

O 4J

u •H CU

u 3 rH rH 4-C 3

•H 5 XJ •H • XJ c0 cd CU o d o z X x 3 CO c0 M M X o 33 o cd 4H 0) cr (U d 3 <U 4-1 <u d 1—1 x o a; *3 4J d C/D cu •H

CO 33

u

O

M CO <U

d 3 o 3

CO 4-* co 0) o O

d 00 •rH cOd

x o d

N co <M o cu

u

<j co CO ai TO CU T3 (U -3 o

CO 00 a) rH co <u XJd

M cu

X

d •H

M

d

a 60 •H

M

d c0 C0 4-> a) j-j

Q

X (U cO

d cu <U XJ >. M CO XJ a 00 d 03 o a> •u • -d <u 60 <u d o •H •H 33 X 60

60

X

d rH

u •H

X rH CO 3 d

•H CO XJ •H rH •H 4-1 XJ o •H

M •H

r—1 a o d c0 3 X CO co > •H (U

d o cu cr 00 X d O CU a 3

c0 o M a- 4-1 0) tH •H o M

X 3 cu

Q

M

O o o M rH 4J o a, XJ co o

CO

V-/ • H d z •H w a s 1 CM

63 3 4-1 3

cd 3 3 4-1 3 M 3 M M X M 3 O 3

O' 3 rH

63

M

w

M

od

M

OO

O

O CMO o O x 0 rH M rH 4-4 4J

C/3 <M ro C cm as 4-1 PQ 4-) o • o O o

&-S S'?

S'?

O 4-1 o

00 rHO rH o co • <u X rH •3 o w O X a CJ z #1 w 00 H rH 2 d • • Cx3 •H CM X i—1

X) o o o w rH X CM o

63 •H * rH CM \ 3 •

1 3 c * r—t

63 PQ

xd ood r-.

d

X • o •— o o o rH •H tH •H

CJ (U L< 4-1

O 4-4 <J 4J 63 o cj m o CJ CJ O O 3 CJ 3 PQ 3 S X C/3 M X X X

Qi

63H XJ H X

<1 60

•H

rH

H

CJ rH

63 3

*“)

U

CO 3 X XJ CO cd z xx3

Cxo 3ado

00c

•Hda

•H

603X

T3

a) 4-) CO

a)m

rt

CO3oc3

l-i 0) <4-1 3

o3

21
asymmetry of radiant effects are other factors that affect human comfort.

(Asymmetry results when there is a large unbalance in the location and temperature level of radiant heating surfaces relative to the occupants of a space.)

Conditions for human comfort are given in ASHRAE Standard 55-81 [30] and are discussed relative to solar applications in section 2.1.5 of reference [31].

Purchasers of passive solar houses expressed strong satisfaction with the

comfort of their houses in a recent survey [29]

.

Radiant heat energy from wall or floor surfaces in passive buildings can be a most comfortable means of space heating (or cooling in the case of heat loss

to surfaces). Discomfort could result due to the effect of asymmetry if such warm radiant surfaces are counterbalanced by a cooling source such as a large

expanse of glazing. Temperature stratification which is common in some passive

techniques may compound the health and comfort problems if temperature changes

are not adequately matched to occupant comfort needs and schedule of activity.

Although the human body can adapt to extreme environmental conditions, it is

evident that thermal discomfort very closely follows physiological strain. The

role of temperature extremes in producing discomfort, incapacity, illness, and

death has been studied over many years but still remains inconclusive. Ordinary seasonal change in temperature climates has an effect on the prevalence

of illness. Most acute diseases and a number of chronic ones vary in frequency

or severity with the time of year [32] . It would be speculative to closely

link the health effects of indoor climate with that of outdoor climate, although

there is always interaction between the two. However, this suggests that frequent changes in environmental conditions in some passive solar buildings may

result in illnesses in a way similar to those resulting from seasonal changes.

Natural passive indoor climate control more closely links the control of the

indoor climate to that of the outdoors than does conventional space conditioning. Reference [33] provides a complete discussion of both outdoor and indoor

climate effects on health including a comfort-health index.

Housing codes require that habitable rooms be maintained at specific minimum

temperatures varying from 26°C (68°F) to 27 °C (70°F) for thermal comfort. Some

local codes refer to standards such as ASHRAE Standard 90-75 [34] which specifies 22°C (72°F) dry-bulb and 26°C (78°F) if air conditioning is used. Some

passive designs operate with greater temperature fluctuations than are allowed

by these standards and therefore may be constrained by them. There may be

inconsistencies in the interpretation of what constitutes a habitable room. For example, solar atriums, sunspaces, etc., may be intended for seasonal or transitory use and specific requirements may not apply. Mass storage walls

and water storage walls or roofs may provide for comfort conditions as radiant

heat sources but with cooler air temperatures than may be required. Also,

ASHRAE Standard 90-75 does not take into account the variation in comfort

requirements that are influenced by the number of people in a space, the

activities ongoing, and the age and health of the occupants.

The different building design requirements raise questions for a variety of

building types that may have varied occupancy patterns. Many commercial

buildings are not occupied during night hours when the most severe heating

loads are likely to occur. This raises the question whether minimum thermal

22
requirements for human comfort must be met during vacant times. Decentralized

and passive heating and cooling systems, which are designed to provide comfortable thermal conditions with changing occupancy loadings, cannot be appropriately

regulated by requirements that have been written for centralized mechanical

systems which provide a constant thermal condition.

4.2.3 Humidity

Excessive levels of indoor humidity can be a problem in tightly sealed buildings

and may further compound the above concerns about elevated temperatures. Passive solar greenhouses may add to humidity levels although there is not adequate

evidence to support the frequently stated concern for this condition.

The role that relative humidity plays in human comfort is closely linked to the

dry-bulb temperature and air movement. Effective temperature combines the

effects of dry-bulb, wet-bulb, and air movement to give equal sensations of

warmth and cold. This has been the best known, and most widely used of all

thermal indices. There is evidence that the upper limit for relative humidity

frequently indicated on human comfort charts can be exceeded if sufficient air

flow is provided in proximity to building occupants [35]. ASHRAE Standard 90-75

requires that if humidification is provided, it must be designed for a maximum

relative humidity of 30 percent. Strict interpretation of this standard may

constrain the use of "swamp" fans for cooling which are likely to result in

greater than 30 percent relative humidity.

Givani cites wetness of the skin and thermal sensation as the two major sources

of discomfort [35]. He also points out that, increased indoor relative humidity

results in a significant reduction in respiratory illness during the winter.

The suggested maximum rate of change of relative humidity is 20 percent per

hour.

Excessive humidity can also create environmental problems in the form of mildew

or fungus growth and condensation. Table 4.3 summarizes requirements for protection against decay and table 4.4 summarizes requirements for venting of

attics. Passive solar techniques such as tightly sealed buildings, movable

insulation, earth contact, cooling tubes, heated rock bins and solar greenhouses

can create the potential for condensation and other humidity problems. Moisture

from the uncovered earth is a significant contributor to condensation problems.

Passive techniques such as envelope houses make extensive use of the earth in

crawl spaces as a heat sink. In contrast to popular opinion, Ralph Johnson,

President of the NAHB Research Foundation states, "the way houses are built

today and in the last ten years does not result in a significant condensation

problem [36]. Burberg refutes this, saying that condensation is becoming more

common and ..."condensation is widespread and is costing millions in remedial measures [37]."

Except for the deleterious effect of excessive humidity and condensation on many building components and human comfort, it is difficult to assess the

level of any health effect. It is acknowledged that some people are particularly sensitive to the effect of humidity and, therefore, will be adversely

affected. The role of humidity increasing the emission of formaldehyde from

23
Table

4.3

Criteria

for

Protection

Against

Decay

and

Termites 3

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24

1/

References

are

listed

on

page

55.
Table

4.4

Criteria

for

Venting

of

Attic

Spaces zo

CO

COO

COw

cjz

cd

a!w

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25
certain building materials and furnishings has been discussed in section 4.1.2.

"Humidity, the one component of air that influences many physiological functions

of the respiratory tract, can also change virus and bacterial survival times;

thus, it could be a significant factor in respiratory health [33J ."

4.2.4 Noise

Noise control is an environmental quality that can be closely associated with

health. Uncontrolled noise can promote stress and interrupt sleep. It is

beyond the scope of this report to discuss extremely high noise levels that

have a more direct effect on health and hearing loss. Overwhelming evidence

suggests that long, continued exposure to noise levels in excess of 85 dBA is

likely to degrade the hearing of a large percentage of humans [38]. This level

(background levels-HC levels) is closely approached by many highways, expressways, railroads, and some industrial areas. Airport approaches may substantially exceed this level. Stenography and duplicating spaces are rated at 50

HC and computer rooms at 70 HC. (In the absence of octave band measurements,

the UC-numbers can be estimated by deducting 7 to 10 points from the dBA measurements in the space.) Ordinary glass is a rather poor sound barrier; therefore, there is a concern for direct gain systems with major sources of noise

from the south. A closed operable single window will typically provide less

than 20 db difference in noise level. Open windows providing ventilation for

cooling will be an even more significant problem. Open planning for buildings

to enhance energy distribution and hard surface materials frequently used in

passive construction may add to the problems of noise transmission inside

building spaces. On the other hand, the frequent use of massive materials,

such as roof pond techniques, earth berming, concrete walls and the reduction

of openings on most of the building perimeter can provide a distinct reduction

in noise, all other things being equal. Multiple occupancies sharing common

areas such as atriums for the capturing and dissemination of solar energy may

be exposing themselves to noises generated in the common areas. However, the

minimized use of mechanical systems such as furnaces, air conditioning, and

fans in passive systems greatly diminishes background noise within the building

interior.

As shown on table 4.5 there is a consensus among building regulations that a sound transmission class (STC) of not less than 45 be required between tenant

units and public areas. Most single glazed assemblies would fail to meet this

requirement. Those techniques requiring air passages from the public space

(corridors, atriums, etc.) may also have difficulty meeting these standards.

4.2.5 Weather Tightness

Passive solar techniques frequently modify the details as well as the concept

of the exterior shell or envelope. These modifications are intended to improve

the capability to collect (or reject), store, and distribute solar thermal

energy. They primarily affect the south wall but some techniques affect other

portions of the building envelope including the roof area. The health concern

for these modifications is that the effort for achieving solar effectiveness

not deeraphasize the traditional role of the building envelope to provide

security and protection from the elements and vermin. Reports and evidence

26
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97
supporting this concern are limited and in most circumstances good practice

could alleviate the problems. A January 1981 report of site visits to passive

houses in the HUD residential demonstration program stated that animals have

penetrated the space between a Trombe wall and a warped glazing panel. In

another instance, snow was stated as entering through a plywood return air

duct. Many plastic films and sheets used for passive glazing expand and contract more than conventional materials and degrade significantly during the

weathering process. Wood framing members, as well as the glazing materials

of some Trombe walls, solar attics, attached greenhouses and wall collectors

are exposed to increased temperature, humidity, and perhaps ultraviolet effects

when used in conventional settings. If materials such as these deteriorate

under these conditions, the membrane may lose its integrity and expose the

interior to outside conditions through penetrations such as ducts, chases, and

vents. Many passive building devices such as double envelopes, cool tubes,

heat exchangers, etc., create a number of crevices, convolutions and inaccessible spaces that can become trouble spots. The idea of a building shell as a system of "filters" is a very sound concept but it requires of the designer

additional attention to construction detail in order to ensure the building

integrity as a shelter from exterior elements.

4.3 FIRE SAFETY

The fire safety issues of passive solar energy systems should be addressed in

terms of the objectives of the fire safety contained in building regulatory

documents. The primary fire safety objective of most building and fire regulations is to prevent the outbreak of unwanted fires and in the event of a fire, provide for the safe egress of the building's occupants. A secondary

objective is to limit the spread of fire to adjacent buildings and properties.

Finally, most building owners, if not the public in general, expect the requirements to limit the spread of fire and related damage within the building of fire

origin.' Frequently this objective will be accomplished to some degree by meeting the primary objective of fire prevention and life safety. The special

requirements for the protection of buildings of high value, special risk, or historical importance will not be addressed in this report.

Although public education is of significant importance in preventing fires and

reducing injury and life loss, the discussion here will be limited to those

strategies normally employed in building and fire regulations to achieve fire

safety objectives. The prevention of unwanted fires is achieved by controlling

ignition sources and the ignitability of materials. Safe egress is provided by

early fire detection, and providing a safe path of travel out of buildings by

limiting the spread of fire and the generation and spread of toxic products of

combustion. The spread of fire to adjacent properties is controlled by requiring

separation distance between properties, limiting the flammability of exterior

building components, and the use of firewalls and fire stops.

Some aspects of passive solar construction may be beneficial to fire safety.

For example, the presence of large volumes of water such as in roof ponds or in

water storage tanks can be helpful in firefighting if they can be properly

tapped. Buildings in Monterrey County, California are required to have a minimum of 1000 gallons of water for firefighting purposes. County officials

28
have given assurance that water used in the passive solar storage devices would

meet this requirement. There is an indication that other counties have similar

requirements, especially those that have frequent forest fires. The presence

of this required water within the building envelope offers the possibility of

its simultaneous use as thermal storage.

The general issues to be examined are control of ignition sources, ignitability

of materials, spread of fire, exterior fire spread, material flammability, fire

detection, means of egress, generation and spread of products of combustion,

and emergency access. Clearly some of these issues overlap. Passive solar

buildings can reasonably be expected to be as safe as conventional buildings of

similar type. Therefore, the fire safety issues will be examined for passive

solar energy systems as they relate to available building and fire codes and

other related regulations.

4.3.1 Ignition Sources

The primary ignition source found in passive solar energy systems, but not

normally found in conventional building designs, is the heat obtained from

solar energy. There have been several fires in active solar energy systems as

a result of the temperature attained in the collector. In one case which has

been documented, the investigation concluded that combustible materials ignited

after being exposed to moderately elevated temperatures for long periods of

time [39, 40]. In another case, plywood in a collector turned into charcoal

as a result of continued heating [41] . Charcoal of this type is believed to

ignite at relatively low temperatures. This problem is complicated by a recent

investigation which indicates that this charring of plywood may have been promoted by fire retardant treatment. The ignition properties of such a material

with fire retardant is uncertain. Additionally, the structural capacity of the

material had been extensively degraded as discussed in section 4.5.

Although the temperatures attained in active solar collectors are generally

higher than those in passive systems, the designs may be similar. The collector in which the plywood turned into charcoal consisted of a single glass

glazing, air space, flat black metal absorber, and a layer of plywood backed by

insulation. The same materials can be found in passive solar systems.

The experience, to date, indicates that the most likely configuration for

material ignition by solar heating consists of a directly irradiated, glazed,

dark absorber surface in contact with a combustible material which is well insulated on the back side. The temperatures at which materials will ignite when

exposed to moderately elevated temperatures for long periods of time are difficult to determine. For example, the most commonly quoted ignition temperature

of wood is on the order of 200°C (392°F) although there have been cases where

wood was ignited after continued exposure to temperatures thought to be slightly

greater than 100°C (212°F) [42] . The ignition temperatures of plastic varies

widely, ranging from lower than wood to much higher. Table 4.6 summarizes

requirements in building regulations for "clearances from heated surfaces."

29
Table

4.6-

Fire

Safety

(Clearances

frooi

Heated

Surfaces)

30

U

References

are

listed

beginning

on

page

55.
4.3.2 Ignitability of Materials

Although a number of tests have been developed to measure the ease of ignition

of materials, they have not generally been incorporated into building regulations. Instead, test methods which measure the tendency for materials to

spread flame are more prevalent in codes. In addition, one can minimize the

intensity of a fire by limiting the amount of exposed combustible material.

Building regulations do not generally limit the amount of such materials which

are not part of the building construction (e.g., furniture). They do classify

materials which are part of the building by specifying limits relative to

building use, type, and zoning requirements. The amount of some combustible

materials such as interior finish is controlled by again limiting the tendency

for those materials to spread flame.

4.3.3. Spread of Fire

Preventing the spread of flame in structures is usually accomplished through

two techniques; providing barriers to the spread of flame and limiting the

so-called flammability of materials.

Barriers against the spread of fire may take a number of forms- The most common

are walls, floors, ceilings and other building assemblies with fire resistance

ratings, the protection of openings through these assemblies, and firestopping.

In addition, many of the requirements typically imposed on ventilation systems

could be considered a type of fire barrier. The primary concern in passive

systems with respect to fire barriers, is the use of unrestricted vertical and

horizontal passageways for air travel. The passageways can take many forms

including openable space between a solar greenhouse and a building, plenums

between atriums and buildings, and the wall cavity within double-envelope

construction.

Regulatory requirements for these air passageways, summarized in table 4.7,

depend to a great extent on whether the air passages are treated as open or concealed spaces within the building or as air ducts or plenums. In general,

the use of uninhabited basements, cellars, crawl spaces, cavity walls, areas

above ceilings or attic spaces as supply air make up, exhaust air, or return

air plenums or ducts is currently prohibited because they are considered as concealed spaces. Regulations require that concealed vertical and horizontal

spaces be fires topped between stories and between building subdivisions. In

addition, many occupancy classes other than one- and two-family dwellings

require that the building be divided into areas each of which is separated from

other parts of the building by fire resistance rated assemblies. These would

typically include fire resistant rated floor-ceiling assemblies and wall assemblies to maintain the maximum area per floor allowed by the regulation. Unprotected passageways for air between these spaces would be precluded. Air ducts

with fire doors or dampers are generally required for penetration of a fire

resistance rated assembly. In addition, ducts which penetrate two or more

floors in other than one- or two-family dwellings, must be enclosed in a fire

resistance rated shaft.

31
Table

4.7.

Fire

Safety

(Vertical

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32

Preferences

are

listed

beginning

on

page

55.
A special kind of shaft or vertical opening between floors is an atrium.

Several model building codes have added requirements for atriums which require

that it be enclosed in fire resistant construction, contain a smoke system, and

that the building containing the atrium be protected with an automatic sprinkler system. The required enclosure of the atrium would require fire dampers for

air passageways between the atrium and other parts of the building.

Firestopping requirements in building regulations are summarized in table 4.8.

The Recommended Requirements to Code Officials for Solar Heating, Cooling and

Hot Water Systems [11] is the only document to specifically recognize that

building code requirements conflict with some passive designs. Commentary in

this document states that:

"1. 'Fires topping' may be omitted in concealed spaces in combustible

construction when smoke activated fire dampers are installed to

cut the vertical draft opening at each floor level in walls and

at each support in roofs.

2. 'Firestopping' may be omitted in concealed spaces in noncombustible

construction when smoke activated fire dampers are installed at

each supply and return air opening. All wall cavities (concealed

spaces) in excess of 200 square inches shall meet the requirements

of a vertical shaft as indicated in appendix XB-1.

Exception: In exterior walls only, the exterior wall of the shaft

need not meet the vertical shaft requirements."

One aspect of fire barrier design unique to passive solar systems is the use

of thermally massive walls, floors, and ceilings to absorb and store heat. In some cases, these building assemblies may have increased fire resistance over

those dictated by normal design, while in other cases, fire resistance may

have decreased. Alternate wall, floor, and ceiling designs should first be

analyzed in terms of conventional design criteria to determine fire resistance

ratings. Often, alternative passive solar designs are conventional designs

applied in unusual ways. However, acceptance of some alternate wall, floor and

ceiling designs may involve testing to meet the fire resistance requirements

of the codes.

4.3.4 Exterior Fire Spread

The objective of the requirements for exterior fire spread is to prevent the

spread of fire from one building to another. It is accomplished by limiting

the combustibility of the building exterior party walls, or providing separation distance between buildings. Generally, there are separate requirements

for exterior walls and roofs. Passive solar systems frequently utilize unique

wall and roof constructions making particular use of light and heat transmiting

materials. This construction may present challenges in providing sufficient

exterior fire protection. Good southern exposure often requires a greater

distance between buildings or building apertures (such as found on the roof) to

the south. This may prove to indirectly solve the problem of exterior flame

spread through separation between buildings.

33
Table

4.8

Fire

Safety

(Fire

Stopping)

Page

O-J 44O I

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References

are

listed

beginning

on

page

55.
1/

References

are

listed

beginning

on

page

55.
The requirements for fire resistance of exterior walls and wall openings are based on the occupancy type of the building, the distance to property lines of

other buildings, and, often, the zoning requirements. Exterior walls of buildings located closer to the property line than a specified minimum distance

are required to have increased fire resistance or the elimination of openings.

Plastic glazing and approved plastic wall panels without a fire resistance

rating may be used in exterior walls subject to limitations based on class of

plastic, fire separation, and the area of the plastic relative to the wall.

The requirements for the fire protection of exterior roof coverings depend on

the type of building occupancy, the separation distance from other buildings

or lot lines and whether or not the building is located within the fire limits.

Fire limits are designated areas in a local jurisdiction for the purpose of

controlling the construction and use of buildings to prevent conflagration

from fire. Fire limits are usually designated in areas containing congested

business, manufacturing, and industrial buildings. Buildings required to be

of fire resistant construction and those located within the fire limits are generally required to have the highest level of roof fire protection. In some instances high sloped roofs may be required to meet the fire resistance requirements of walls. This may restrict passive techniques where roof related solar

apertures are sloped steeply to provide for the correct angle to the sun.

The use of light transmitting roof panels or skylights is of particular

significance in many passive solar designs. Regulatory requirements for light

transmitting roof structures differ somewhat between the documents evaluated

and are all fairly complex. The requirements are different based on whether

the material is glass or plastic. In most cases, glass skylights are required

to be glazed with wired or tempered glass or plain glass with a protective

screen. Although there is generally no maximum area for skylights there may be

a maximum area for individual panels of glass. Areas may be limited due to

roof access for firefighting and safety of the occupants on the interior.

Plastic roof panels are structural panels and may generally be installed in

buildings where the roof is not required to have a fire resistance rating.

Depending on the type of plastic and the regulation to which the building is

designed, individual panels cannot exceed 9 m^ (100 ft^) to 27 e&2 (300 ft^) with

a maximum aggregate area of 25 to 33-1/3 percent of the floor area. Individual

panels must be separated from each other by a minimum of 1.22 m (4 ft). Panels

must not be installed closer than 1.83 m (6 ft) to 2.44 m (8 ft) from an exterior wall required to have a fire resistance rating. The requirements for

plastic skylights are similar to those for roof panels except skylights are required to be mounted on curbs constructed 10 cm (4 in) above the roof. See

table 4.12 for a summary of glazing requirements in building regulations.

The primary test method used in evaluating light transmitting plastic is ASTM

D635, Standard Test Method for Rate of Burning and/or Extent of Time of Burning

Self-supporting Plastics in a Horizontal Position. There are no studies known

which correlate the results of the small scale tests with actual building fire

performance

.

36
4.3.5 Material Flammability

The material flammability concerns of most importance to passive solar energy

systems are those related to interior finish materials and duct linings and

coverings. Interior finish materials are usually classified in accordance with

test method, ASTM E84, Surface Burning Characteristics of Building Materials.

Table 4.9 is a summary of related requirements in building regulations.

The requirements for interior finish materials vary greatly depending on occupancy and location of the materials within the occupancy. A primary

concern with the use of interior finish materials in passive systems is with

materials used for insulation. Unlike conventional construction, some passive

systems may involve the extensive use of insulation within the structure rather

than around the perimeter. Exposed insulation other than plastic foam will

generally have to meet a requirement of an interior finish for the given location. The requirements for foam plastics are more specific. Foam plastics

which have a flame spread of 75 or less may be used when fully protected by a thermal barrier of fire resistive materials having a finish rating of not less

than 15 minutes. One-half inch thick gypsum board will normally meet this

requirement. Foam plastics with flame spread of 25 or less may be used in

certain cases when covered by an aluminum or steel sheet and the insulated

area is protected with automatic sprinklers.

Regulatory requirements for movable insulation including special drapes and

interior shutters are not clear. If the insulation is considered part of the

building, then it may have to meet requirements of an interior finish. If

the insulation is considered a trim and is not in excess of 10 percent of the

total wall and ceiling area, then a less stringent requirement would be imposed.

Since plastic materials are desirable for much of this insulation, it may be

necessary to study the actual fire performance of typical insulation

conf igurations

.

Duct coverings and linings have separate flame spread requirements. In one- and two-family dwellings, duct coverings and linings must have a flame spread

rating not over 25 to 50 depending on the building regulations. In other than

one- and two-family dwellings, duct coverings and linings must have a flame

spread rating not over 25. Ducts are generally required to be constructed of

approved materials such as steel, iron, aluminum, concrete, or approved fibrous

glass. Return ducts of materials no more flammable than one-inch boards may be

used in one- and two-family dwellings.

4.3.6 Fire Detection

The primary concern in the area of fire detection for passive solar systems

would appear to be the location of smoke detectors in residential occupancies,

particularly one- and two-family dwellings. It is generally recognized that

smoke detectors shall be placed in hall areas leading to rooms used for sleeping

purposes. In cases where unusual air movement is involved, additional detectors

or alternative locations may be necessary. In residences with passive solar

systems, particularly designs like the envelope house, alternative paths for

smoke travel may be present. These paths may permit smoke to reach the sleeping

37
Table

4.9

Fire

Safety

(Material

Flammability) 1 O G 4-1 CO r—1 X c H g s 3 X JC o o • a ft X a> to CU CO •H < 4-1 4-J c M •H c AJ a; ft J CO X X c o cd M 3 o 4-1 3 •H X 1—1 •H

i—i

co

O CO <D CT 4-1

X

d

d \ X CU cO CO cr

c/ou CO

H

X l-i 34 • 3 c QJ 2 > C cd CO o co ,—I

•H

u

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X o r—1 > CU •H

X cO i—l

co

X o o X 34

C > a) CO

H co 4-1 CO s CU CU cu > •H < < U X a •H

CJ CL,O <v co

G c CU

X 4-) CO

M ft, > to e X >4 3 cd S J 2 •H •H X > a> ft O (0 CO X c X 3 <u o 4J e CO a o a) cr u c CO X o cd 3 •H cu <U G a

co CL CO

X S 34 cj •H CO o o •H X • •H AJ c X G CO U CO G cu X a cu

X <U cd cu 3 co o AJ rH co CO X X G 2 c a CL G CO CNJ G g O •H X X M o e "3 X G X a) cu CO X) *—1

cd CU coX o a

a

CO rH o CO

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CD co cd (H 3 c CU XI

X to o X •rH X G X

CO c O a)X

G CU

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CU

d <u

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cr

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r-

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X o X

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Cd L—1 o _ <u >—• o i i O >—• O 1 3 o O rH H AJ X rH *H •H *H o G c 4J O ft O x G < AJ O x CJ AJ cj X CJ G CQ G O G X CJ G X G CJ G O o G Cd X X G O o G CJ G X G S PQ CO X o CO CO 2 X CO X co X CO

cd

X CO Cd CO G H •H *H H c 4J •H 34 CO 2 Ch O cd rH H 34 34 ft O O G

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CQ

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38
areas without entering the hallway and activating the smoke detector. An

example of this situation would be where windows in sleeping areas open to an

inside area such as an atrium or greenhouse.

4.3.7 Means of Egress

Means of egress requirements summarized in table 4.10 can be readily

incorporated into most passive solar designs if their consideration is given

during the design stage. The exit requirements for one- and two-family dwellings may be of particular concern in the design of some passive systems. Most

building regulations require two means of escape from every bedroom, at least

one of which must be a door or stairway leading to the outside of the building

at ground level. Traditionally, the second means of escape has been provided

by a door or window leading directly to the outside of the building. Many

energy efficient and passive solar buildings' designs seek to eliminate windows

in north-facing bedrooms. Several model building codes now permit the second

means of escape to be a door or stairway providing a means of unobstructed

travel to the outside of the building. Some do not require a second exit if

the primary exit leads directly outside of the building at ground level and if

the dwelling is protected throughout with an approved automatic sprinkler

system.

4.3.8 Generation and Spread of Products of Combustion

Although it has long been recognized that the control of products of combustion

is one of the most important fire protection strategies available, it has been

one of the most difficult to implement. Most current regulatory requirements

deal with limiting the visible products of combustion or smoke. Methods of

measuring other toxic products of combustion are being developed. These measurement methods must then be coupled with criteria for the maximum acceptable

level for these products and then be converted into regulatory requirements.

At present, the limited smoke development requirements are based on ASTM E84

,

Surface Burning Characteristics of Building Materials. The requirement of

particular significance to passive solar systems are those for duct coverings

and linings. The maximum smoke development rating for duct coverings and

linings varies between 25 or 50 in regulatory documents depending on where the

duct is to be used.

Special smoke control measures are required to protect egress paths from

buildings. Control of smoke spread is frequently accomplished by the same barriers used to control fire spread. These usually consist of smoke-proof

towers or enclosures. Smoke control requirements vary widely depending on the

regulations and type of occupancy. Although smoke control is not required in

one and two family dwellings and many small commercial buildings, consideration

should be given to the smoke movement risks associated with many passive designs.

Passageways designed for the movement of heated air throughout the building may

also be very efficient at moving smoke. Passive systems generally utilize large

air passageways and are designed to take advantage of natural convection both

of which may be an aid to rapid smoke movement. There are no standards for

installation of smoke control systems in one- and two-family dwellings and the

39
Table

4.10

Fire

Safety

(Means

of

Egress)

C/3 <4-4 AJ 0) • H O O rd a

CJ 60

d AJ a)

03 4J c AJ C d •H 03 >» CO S o o 03 OJ r-4 rd >N M CO 4-) —

d CO \ CO u *H o 03

COw •H o d Si 0)

u 2 > CL rd CO CO 03 O H >* e t4 r—4

i—i

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CJ CL, 03 CO 0) CL a> i—I

CO o 4-)

d e > J 2 a o 60 o •H

CL. o 03 03 •H cj CO s 44 0) CL CO CO 1—1

•H rd CO <0 ii

03 aJ AJ 03 03 CL

4J 0) Li CJ

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03 AJ a) 4-4 2 44 AJ o CL 03

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i—tC -5 CO CO AJ > o a jr 03 Li

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CO (0

d

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CJ CO 03 s 03

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X Li

d >% CO cj L4 •H Li 03 o a) o o O w 03 AJ 03 d o Li 44

r—4

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40

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References

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listed

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55.
wide variety of passive designs indicates that the smoke control system must be

designed for the particular application. The primary objective of smoke control

is to protect means of egress and may be integrated with the smoke detection

system. In some passive solar buildings, there may be a possibility of linking

a smoke control system with the heat exhaust or passive ventilation system.

4.3.9 Emergency Access

The primary consideration in passive systems relative to emergency access is

firefighter education. As a result of their design, passive buildings may be

similar in appearance to conventional construction even though they may contain

unconventional paths for smoke and fire travel. Commercial and industrial

buildings are usually inspected by the fire departments in medium and larger

cities. During these inspections, the features of the passive system which

affect firefighting tactics can be noted. However, one- and two-family dwellings are rarely inspected and the fire department may not be aware that a house has a passive system. Features such as double walls and roofs, and

building components which serve as air passageways may hamper rescue efforts

and delay location and control of the fire.

4.4 STRUCTURAL CONSIDERATIONS

Some passive solar buildings have construction details which are not that common in conventional structures. These include: (1) large glazed spatial

areas on the building exterior concentrated on the south-facing side; (2) thermal mass (e.g., roof ponds, water-filled columns, concrete block walls) located

within the interior of the building for the storage of energy; (3) excavations

adjacent to the foundation for the placement of storage tanks, underground piping, etc.; (4) large open interiors used as greenhouses, atriums and solariums;

and (5) earth covered structures. Structural design procedures are sufficiently

well developed to provide for the safe utilization of such features. Loadings,

desiccation of wood, and glazing considerations will be discussed in some detail below.

4.4.1 Loadings

Table 4.11 presents a summary of structural design criteria contained in

current building regulatory documents. The design of passive solar constructions should be easily accommodated within these criteria. Special consideration is needed for solar retrofit situations when thermal mass is added within

the existing structure which has an unknown load capacity. Generally, this

includes the large amount of mass which is present in most passive buildings

for thermal storage which may or may not be an integral part of the structure.

However, mass in the form of free-standing concentrated loads placed inside or adjacent to occupied spaces are not directly addressed in current building

regulations. Large water containers weighing over 190 kg (417 lb) are frequently stacked, suspended, or placed vertically within the building envelope.

This practice raises the issue of container stability. The frequent placing of

these containers near large expanses of glass makes structural stability of

these stacked units even more critical. Restraint from overturning of these

41
Table

4.11

Structural

Design

Criteria

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ii/

References

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listed

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on

page

55.
storage devices can be simply achieved but frequently is not provided.

Buildings located in areas of seismic activity will potentially have a more

severe problem. Water movement behavior and the tendency to "slosh" must be

considered for the stability of large containers of water which could be

affected by earthquake or other impact forces.

Earth covered structures are a type of passive solar design which provide some unique structural design considerations. Researchers at Minnesota University

[46,47] have analyzed code problems unique to this type of building and have

identified the following structural design issues:

a. design loads on an earth covered roof may be five or more times

greater than on a conventional roof;

b. completely buried walls must be designed to resist significant

lateral forces (e.g., hydrostatic pressure);

c. soil tests may be required due to the high loads on earth covered

houses;

d. waterproofing of below ground roof and walls found in this type of

building is directly addressed in current codes;

e. design by a licensed engineer may be required even for conventional

framed structures because of unique loading conditions.

4.4.2 Desiccation of Wood

A structural concern that is not addressed in building regulations and is

somewhat unique to solar applications is the desiccation of wood support members. Prolonged exposure to elevated temperatures, on the order of 100°C

(212°F), significantly reduces the structural capacity of wooden members.

Some passive solar techniques, such as solar attics and wall air collectors,

expose wood structural and framing members to elevated temperatures. During

periods of stagnation, when heat energy is not being removed from the collection area, temperatures can approach a level at which significant desiccation

can occur. In general, the mechanical properties of wood decrease when heated

and increase when cooled. This effect is immediate, but prolonged exposure at

high temperature causes an irreversible decrease in properties. At a constant

moisture content and below about 204°C (4Q0°F), mechanical properties are essentially linearly related to temperature. Inberg has shown that, in com- pression, several species of wood lost 50 percent of their strength at a temperature of about 106°C (222°F); the temperature-strength relation in the

range from ambient to 100°C (212°F) being roughly linear [48].

A conclusion by McGuire states that if a long service life is desired, wood

under service conditions should not be exposed to temperatures appreciably

higher than 66°C (151°F) [49] . Exposed framing members may be supporting

unusual dead loads, such as mass for thermal energy storage. In some cases,

the presence of storage mass may form a heat sink and help to retard the maximum temperature to which wooden support members are subjected. However, the

43
possible strength reduction of wood framing members caused by exposure to

elevated temperatures, somewhat unique to passive solar applications, is a potential problem of which designer/builders should be aware.

Some recent occurrences seem to support this concern relative to wood

dessication. One involves a "solar attic" and two others involve site built,

active roof collectors. The solar attic house is located in California and is

a solar demonstration project sponsored by the Department of Housing and Urban

Development. Elevated temperatures have been recorded in the attic space as well as in the structural framing members. Under stagnation conditions (no air

flow or venting) 81°C (178°F) was recorded in the attic when outside ambient

was near 32°C (90°F). A temperature of 95°C (203°F) was measured 11.4 cm

(4.5 in) into the wood of a rafter supporting the glazed roof which serves as

the collector of this solar attic. The plywood flooring of the attic was badly cracked and partially delaminated. Gypsum wallboard on the vertical

surface of the back of the attic was dried out and powdery. Also, lag bolts

which fastened the glazing battens to the rafters were pulling loose.

Another investigation involved a site-built, active air system integrated

into the roofs of condominium units in New Hampshire. Again temperatures of

approximately 98°C (208°F) were measured well into the interior of rafters

supporting the absorber plates of these air collectors. Foil faced insulation

boards immediately behind the absorbers had surface temperatures of 105°C

(222°F) and 92°C (197°F) inside the board. Some discoloration was observed

suggesting physical deterioration of the foam insulation. Attic temperatures were in excess of 65°C (150°F) even though the collectors within the roof plane

prevented direct solar radiation into the attic. These attics extended over more than 76 m (250 ft) of open space. Building codes frequently limit

concealed roof spaces to 279 m^ (3000 ft^) or less, or they must be subdivided

with approved fire stops.

This occurrence suggests that joints and connections in wooden members may be

especially vulnerable to the desiccation phenomenon. Metal elements used in

such connections including nails, bolts, screws, and connectors may conduct

elevated temperatures deeply into the wooden members. The resulting desiccation at these points may weaken the joint significantly and render the connection ineffective. As stated earlier, the wooden members themselves would be

weakened at elevated temperatures but joints and connections are frequently the

critical elements of a structural component. One conclusion is that collection

spaces such as these either must not be allowed to stagnate or they must be

built of materials that will withstand elevated temperatures. Shading of the

structure, fail safe venting, careful detailing of joints, and connections are

some techniques that should be considered.

Other investigations involve several site-fabricated, active liquid collectors

in which the collector/absorber backing consists of 0.95 cm (0.375 in) to

1.90 cm (0.75 in) plywood sandwiched between thin sheets of copper and aluminum.

These panels also serve as the only roof sheathing of the buildings. Investigations at several sites, notably in South Carolina, have shown that the plywood of some panels has been reduced to a charcoal appearance by the high

44
temperatures and has lost structural integrity. This condition has been

observed for at least ten other sites.

There have been some troublesome inconsistencies revealed in these

investigations. There are cases where panels adjacent to severely charred

ones have little or no discoloration. It has been suggested, and tentatively

supported by Forest Products Laboratory (FPL), that fire retardant treatment

may promote the charring and degradation of the plywood in such circumstances.

Inadvertently, some panels may not have been treated with fire retardants.

This raises the dilemma that fire retardant treatment may be a necessary

precaution against potential ignition but may also promote the structural

deterioration of these materials.

4.4.3 Glazing Considerations

Broad expanses of glass are frequently used in both conventional residential

and commercial construction. Passive solar design practices tend to consolidate glazing on the south faces of the building, with significant reduction of

windows on the north, east, and west sides. Often the total amount of glazing

used in the building is not significantly increased over typical building

design.

Glass is the most common glazing material used in passive solar, although a wide variety of plastic glazings are also used. Glass breakage constitutes one

of the most commonly acknowledged physical hazards in residential buildings.

Each year, in the United States, there are approximately 215,000 injuries

involving glass breakage in residential windows [50] . The following applications, representative of some of the prevalent uses of glass in passive solar

systems, may increase the hazard potential even above the normal incidence of

glass related injuries: glass skylights and roof panels; sloped areas of

glass; mass storage units adjacent to glass panels; glass installed very close

to floor level; and glass installed adjacent to doorways and general circulation patterns. Large glazed areas are of particular concern in those parts of

the country in which earthquakes are prevalent. There is a significant amount

of seismic activity in the west and southwest where there is a strong interest

in passive solar construction. Additional passive applications of glass that

may have safety implications include: the use of multiple glazings, large temperature fluctuations (affects expansion and contraction, and potential thermal

shock), and increased glare and reflection in the vicinity of the glazing.

The use of safety glass, such as tempered glass, laminated glass, or perhaps

wire glass, will resolve most of the dangers associated with glass breakage.

Careful attention to detailing and the use of restraining devices or rails will

also help reduce safety problems. Present building regulatory requirements

offer adequate guidelines for these practices.

Regulatory provisions which relate to the structural design of glazing are

summarized in table 4.12. Criteria considered are structural support of glass,

human impact, wind loads and limits of glass area, sky light design requirements, and the design of plastic glazing.

45
Table

4.12

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47

References

are

listed

beginning

on

page

55.
Table

4.12

Glazing

Design

Criteria

in

Codes

(continued)

Page 3

of

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48

References

are

listed

beginning

on

page

55.
Table

4.12

Glazing

Design

Criteria

in

Codes

(continued)

Page

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49
Table

4.12

Glazing

Design

Criteria

in

Codes

(continued)

Page 5

of 2OaHO<

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50

}J

References

are

listed

beginning

on

page

55.
Provisions for structural support of glazing are generally presented as maximum

areas depending on glass type, thicknesses, and design wind loads. This could

constrain a passive solar designer who may want to use glass more extensively

than regulations would allow and could require a greater level of design. For

example, three of the model codes (BOCA, ICBO, and SBCC) specifically require

that detailed drawings, specifications, and designs be submitted to the building official for approval when glass is used which is not supported along all

four edges. The potential for injury due to impact of the glass should be

thoroughly considered.

Glass used in skylights and roof panels creates an additional safety problem

because of the hazard of broken glass falling into occupied spaces. Building

codes generally require that glass used in skylights be tempered or wire glass,

or have screens installed both above and below the skylight. Skylights sloped

less than 45 degrees must be on 0.1 m (4 in) curbs. Skylights must also be

designed to carry all tributary roof loads. There has been some concern stated

that the presence of large areas of skylights would inhibit access and mobility

of firefighters in an emergency. For this purpose, roof obstructions are frequently limited to 1/3 of the roof area. The distinctions between skylights,

glazed roof panels, and sloping facades which are glazed are not well characterized in building regulations and could lead to some confusion with unusual

passive applications in determining compliance.

Safety glazing is required for the glazing of entrance doors and for panels

adjacent to entrances and walkways if the panels are larger than 0.46 m (18 in)

in any one direction and are less than 0.46 m (18 in) from the walkway surface.

The Consumer Product Safety Commission (CPSC) has revoked the part of its

standard that affected "glazed panels" or glazings next to doors and between

two walking surfaces [51]. However, the major model code groups have indicated

that they will provide this coverage. Glazed doors rank among the top ten

hazardous consumer products. Sliding glass doors are specifically covered in

the model codes and are primarily based upon the voluntary standard for safety

glazing, ANSI Z97.1 [52]. Sliding glass doors are sometimes used in passive

designs for uniformity and potential ventilation in places not intended for use

as entrances or doorways. The strict enforcement of the codes may require that

such applications use safety glazing.

4.4.4 Summary

The structural design of buildings with passive solar techniques appears to be

well-covered by the six regulatory documents included in this study. In cases where an analytical approach may not provide a reliable assessment, building

codes allow prototypical testing to evaluate performance. There will be the

need for more rigorous structural analysis and design and less reliance on handbook solutions since many of these techniques differ from current conventional practices. As passive solar design becomes more widespread, these

innovative practices will become part of the general practice.

51
5. SUMMARY AND RECOMMENDATIONS

While much of the technology required for application of passive solar

techniques in buildings is the same as conventional construction, there are many issues of a health and safety nature which are quite different and

require further study and research. The drive to experiment and optimize

thermal performance in buildings may introduce new and unusual health and

safety considerations, as well as some questionable building practices.

Building codes which regulate how buildings are constructed do not adequately

address all these issues, even though there have been recent attempts to

develop codes for the unique conditions associated with passive solar design.

The summary and conclusions of this study are as follows:

a. There is increasing evidence that correctly designed passive solar

buildings have comfort characteristics which equal or exceed con- ventional buildings. Overall comfort is enhanced by the thermal

stability of a well insulated building with large thermal mass used

for storage of solar heat.

b. There is growing concern for the potential effects on health associated

with a deteriorated indoor air quality in passive solar heating and

cooling. This concern primarily results from the decrease in air

infiltration and air movement in passive buildings. Other concerns

are elevated temperatures at the point of collection/absorption of

solar energy; increased humidity and potential for condensation, mold,

etc.; and passage of air streams through structures. A reduction in

fossil fuel combustion will help reduce the amount of particulate

matter and thereby result in an improvement of the quality of indoor

air.

c. Some materials and techniques common in passive solar buildings are believed to contribute to the concentration of contaminated air.

The reduced level of air infiltration which passive solar technology

shares with other energy conserving practices is known to contribute

to this concentration. Prominent indoor air contaminants are formaldehyde, radon, and rock storage beds (dust, odors, mildew).

d. Structural design procedures are sufficiently well developed to provide

for the incorporation of passive solar energy features in buildings.

e. The design of glazing for passive solar applications is well within

the current state-of-the-art. There are unique concerns such as temperature fluctuations and the increased potential for injury from

accidents that must be considered.

f. Passive construction techniques usually provide increased protection

from physical forces such as storms and explosions. The increased

use of masonry provides less combustible materials, reduced sources

of toxic fumes, and perhaps increased stability against collapse.

52
Masonry construction may also serve to help the control of fires

through corapartraentation and aid in fire confinement by preventing

spread to adjacent building.

g. There is strong evidence that heavy use of heating appliances

increases the incidence of fire. Data indicates that about 10 percent more fires per 1000 population occur in the northern states

compared with those further south. Similar correlations for winter

versus summer months and with the severity of winter weather give

further indication that over-all fire incidence is related to the use of energy. The fact that passive solar buildings generally

use significantly less fossil fuel energy is an additional factor

in fire safety. Passive solar buildings also tend to have less

ductwork than those with conventional forced air HVAC distribution

systems, resulting in a reduced risk of fire spread through ductwork.

h. In general, the use of uninhabited basements, cellars, crawl spaces,

cavity walls, areas above ceilings, or attic spaces as supply air

make-up, exhaust air, or return air plenums is prohibited by present

building regulations. Concealed vertical and horizontal spaces must

be firestopped between storys and between building subdivisions.

Unprotected passageways for air between these spaces would be precluded and air ducts with fire doors or dampers are generally

required for penetration of a fire resistance rated assembly.

i. There are serious economic implications in applying existing

building code provisions when solar retrofitting an existing building. Costs of modifications could trigger the ”25-50 percent rule"

and require compliance with the code for new construction. CABO

[11] has incorporated a requirement which alleviates this problem.

Recommendations for further research and changes in building regulations

needed to accelerate the acceptance of passive solar energy systems are as follows

a. Investigation of selected building materials prevalent in passive

solar construction is needed to determine the level of air pollutants

emitted under varying conditions of air movement, temperature, and

humidity. Low cost techniques should be developed to measure and

monitor the pollutant level of selected pollutant categories in

tightly sealed buildings.

b. Additional research is needed regarding the long term effects of

elevated temperature on the structural capacity of wood. Research

is also necessary on how wood treatment practices (such as fire

retardation) affect the the structural capacity of wood when this

treated wood is exposed to elevated temperatures.

c. Building codes should be analyzed and alternative guidelines

developed to reduce the impact of the codes restricting the area of

skylights and roof panels to 25 to 30 percent of the area covered.

53
d. The primary concern in the area of fire detection for passive solar

systems involves the location of smoke detectors in residential

occupancies. Guidelines should be developed for the placement of

smoke detectors in residences with passive solar systems. Guidelines

should address: (1) unusual paths of smoke travel, (2) combination

with fire dampers and sprinklers, and (3) existence of special

environmental conditions such as high temperatures.

e. Analysis of building code requirements for barriers to fire spread

indicates that the code provisions generally were not written with

passive solar systems in mind. For instance, are the air passageways in the attic and crawl space in an envelope dwelling considered

uninhabited spaces or plenums and can the air space along a Trombe

wall be considered an atrium? Modifications to building regulations

are needed to clarify which requirements would be appropriate for

passive solar systems, or at least, the objectives of fire spread

requirements should be clearly stated in order that the designer may

have the opportunity to fulfill them through alternative solutions.

f. The primary test method used on evaluating light transmitting

plastics is ASTM D635. There are no studies now which correlate

the results of the small scale tests with actual building fire

performance. Since light transmitting plastics are incorporated

in many passive solar designs, a study of this type is needed.

g. Research is needed on the effect of high temperatures on the

performance of materials used for passive solar systems.

h. Material flammability concerns of most importance to passive solar

energy systems are those related to interior finish materials and

duct linings and covers. The primary concern in passive systems

with the use of interior finishes are those used in insulation.

Code requirements for movable insulation including special drapes

and interior shutters are not clear. Code requirements for movable

insulation need to be clarified. Since plastic materials are desirable for much of this insulation, it may be necessary to study the

actual fire performance of typical insulation configurations.

i. Second means of egress may be a potential problem since many energy

efficient and passive solar building designs seek to eliminate

windows in north-facing bedrooms. Technical justification should

be developed for regulator acceptance of alternate solutions which

provide equivalent performance.

j. Beyond the obvious needs for a better understanding of the toxic

products of combustion and their effects on humans, smoke movement

in passive solar buildup should be studied further. Computer models

are being developed to study smoke movement in buildup with conventional HVAC systems and those models may provide useful information

when applied to passive solar designs. Guidelines should be developed for the installation of smoke control systems in buildings

with passive features.

54
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,

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,

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9. Cooke, P. W. and Eisenhard, R. M., A Preliminary Examination of Building

Regulations Adopted by the States and Major Cities , National Bureau of

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Technology, Department of Housing and Urban Development, Washington, DC,

NTIS PB80-135692 , 1977.

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and Hot Water Systems, Council of American Building Officials (for DoE),

DoE/cs/34281-01, June 1980.

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Regulations on Rehabilitation - Status and Technical Needs , NBS

Technical Note 998, May 1979.

13. Rehabilitation Guidelines, Volume 1, Guidelines for Setting and Adopting

Standards for Building Rehabilitation , Department of Housing and Urban

Development, HUD-PDR-613-1 , Washington, DC.

14. Environment, Health and Safety, and Social Impact , DoE Solar Energy

Program Summary Document - FY81, January 1980.

55
15. Bregsse, P., The Health Cost of 'Tight* Houses , Journal of the American

Medical Association, Vol. 245, No. 3, January 16, 1981.

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of Urea-Fomaldehyde Foam (A Residential Insulation, Part I: The Effects

of Temperature and Humidity on Formaldehyde Released from Urea-Formaldehyde

Foam Insulation (for DoE), ORNL/SUB-7559/1, University of Iowa, September

1979.

18. Godish, T., Recognition of Building-Related Illness , Natural Resource

Notes, Ball State University, 1981.

19. Harris, J. et al.. Toxicology of Urea-Formaldehyde and Polyurethane

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20. Hadley, J., Energy Conservation and Indoor Air Quality , ASHRAE

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21. Swedjeraark, G. , Radon in Dwellings in Sweden , Symposium on Natural

Radiation Environment III, Houston, Texas, 1978.

22. Scott, L. and Scoll, M., Indoor Air Pollution in Passive Structures , Proceedings, 5th National Passive Conference, Amherst, MA, October

1980.

23. Kusuda, T., Hunt, C. and McNall, P., Radioactivity (Radon and Daughter

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24. The Radiation in Sun Homes , The Swedish National Institute for

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25. Silberstein, S., Radon in Six Test Buildings at the National Bureau of

Standards , National Bureau of Standards Letter Report, Part 1 (September 1981) and Part 2 (December 1981).

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Housing and Urban Development, HUD Circular 4900.1, Washington, DC, 1980.

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28. Standard for Ventilation for Acceptable Air Quality , American Society of

Heating, Refrigerating and Air Conditioning Engineers, ASHRAE Standard

62-81, New York, NY, 1981.

56
29 . Residential Solar Demonstration Programs: Findings of the Passive Solar

Residential Design Competition and Demonstration , Real Estate Corporation,

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30 Thermal Environmental Conditions for Human Occupancy , Standard 55-81,

ASHRAE, 1981.

31. Metz, F. E. et al.. Performance Criteria for Solar Heating and Cooling

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32. Health and the Environment , ASHRAE Fundamental Handbook, ASHRAE, 1977.

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Atlanta, GA.

35. Loxsom, F. ed.. Passive and Hybrid Cooling Workshop Handbook , Philadelphia, PA, May 1981.

36. How to Avoid Condensation Problems , Housing, April 1981.

37. Burberg, F., Condensation, How to Avoid It , Architectural Journal,

October 1979.

38. Yerges, L. , Sound, Noise, and Vibration Control , Van Nostrand

Reinhold, New York, 1969.

39. Harvey, C. S., Fire Occurs Within Solar Panel , Fire Command, Vol. 47,

No. 9, pp. 40-41, September 1980.

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Bureau of Standards, NBSIR 80-2326, Washington, DC, August 1981.

41. Moore, D. C., Lessons Learned from the HUD Solar Demonstration Program , Solar Engineering, pp. 16-18, 45, March 1981.

42. Ignition of Wood and Wood Products , Fire Protection Handbook, Fifteenth

Edition, pp. 4-11 and 4-12, Quincy, MA, September 1981.

43. Basic Mechanical Code , Building Officials and Code Administrator

International Inc., Homewood, Illinois, 1978.

44. Standard Mechanical Code , Southern Building Code Congress International,

Inc., Birmingham, Alabama., 1980.

45. Uniform Mechanical Code , International Conference of Building Officials,

Whittier, California, 1979.

57
46. Earth Sheltered Housing Design, Guidelines, Examples and References , The

Underground Space Center, University of Minnesota, Minnesota Energy Agency,

Van Nostrand, Reinhold, NY, 1980.

47. Earth Sheltered Housing: Code, Zoning, and Financing Issues , University

of Minnesota, NTIS No. PB81-118150, April 1980.

48. Wood Handbook: Wood as an Engineering Material , Forest Products Laboratory,

Agricultural Handbook No. 72, August 1972.

49. McGuire, J. H., Limiting Safe Surface Temperature of Combustible Materials , Fire Technology, August 1969.

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December 1978.

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.

52. Performance Specifications and Methods of Tests for Safety Glazing

Material Used in Buildings , ANSI Standard Z97.1a - 1977, New York, NY.

58
NBS-114A (rev. 2 -eo) U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET (See instructions)

4. TITLE AND SUBTITLE

PUBLICATION OR

REPORT NO.

2. Performing Organ. Report No. 3. NBSIR 82-2554

Publication Date

August 1982

HEALTH AND SAFETY CONSIDERATIONS FOR PASSIVE SOLAR HEATED AND COOLED BUILDINGS

5. AUTHOR(S)

F. E. Metz, J. H. Pielert, P. W. Cooke, D. Walton

6. PERFORMING ORGANIZATION (If joint or other than NBS, see instructions) 7. Contract/Grant No. national bureau of standards

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

DE-AI01-76PR06010

8.

Type of Report & Period Covered

Final

9. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street. City. State, ZIP)

U.S. Department of Energy

Office of Solar Heat Technologies

Passive and Hybrid Solar Energy Division

Washington, D.C. 20585

10. SUPPLEMENTARY NOTES

Document describes a computer program; SF-185, FIPS Software Summary, is attached.

11.

ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bibliography or literature survey, mention it here) Passive solar buildings often introduce alternative construction techniques, and new materials and applications which presently have limited guidelines concerning

safe application. This report discusses research conducted to pursue the nature

of health and safety considerations in application of solar passive technology

to buildings and how they would be affected by current building regulatory

requirements. Health and safety considerations associated with solar passive

systems are discussed including: indoor air quality; structural safety; fire

safety; and environmental issues such as ventilation, illumination, temperature

control, humidity and noise control. The report also identifies technical

issues and research needs for addressing health and safety issues in passive solar

technology.

12.

KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolon s) Buildings; building regulations; energy; enforcement; health and safety; passive

design; solar energy; standards.

13.

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