ASTM_C_1744_-_12.pdfVIP免费

 Designation: C1744 − 12

 

Standard Practice for

Installation and Use of Radiant Barrier Systems (RBS) in Commercial/Industrial Building Construction1

 

This standard is issued under the fixed designation C1744; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (ε) indicates an editorial change since the last revision or reapproval.

 

 

1.  Scope

1.1  This practice has been prepared for use by the designer, specifier, builder, and the installer of radiant barrier systems (RBS) for use in commercial/industrial building construction not  otherwise  restricted  from  use.  The  scope  is  limited  to instruction relative to the use and installation of RBS, includ- ing a surface(s) normally having an emittance of 0.1 or less, such  as  metallic  foil  or  metallic  foil  deposits,  mounted  on substrates.  Some  examples  that  this  practice  is  intended  to address include: (1) low-emittance surfaces in vented building envelope cavities intended to retard radiant transfer across the airspace: (2) low-emittance surfaces at interior building sur- faces intended to retard radiant transfer to, or from, building inhabitants; and (3) low-emittance surface at interior building surfaces intended to reduce radiant transfer to, or from, radiant heating or cooling systems.

1.2  This practice covers the installation process from pre- installation inspection through the post-installation procedure. It does not cover the production of the radiant barrier materials. (See Specification C1313.)

1.3  This practice is not intended to replace the manufactur- er’s installation instructions but shall be used in conjunction with such instructions. This practice is not intended to super- cede local, state, federal, or international codes.

1.4  This practice assumes that the installer possesses a good working knowledge of the applicable codes and regulations, safety practices, tools, equipment, and methods necessary for installation of radiant barrier materials. It also assumes that the installer   understands   the   fundamentals   of  commercial/ industrial building construction that affect the installation of RBS.

1.5  The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.

 

1 This practice is under the jurisdiction of ASTM Committee C16 on Thermal Insulation and is the direct responsibility of Subcommittee C16.21 on Reflective

Insulation.

Current  edition  approved  May   1,  2012.  Published  May  2012.  Originally approved  in  2010.  Last  previous  edition  approved  in  2010  as  C1744–10.  DOI: 10.1520/C1744–12.

 

 

 

1.6   This  standard  does  not purport  to  address  all  of  the safety  concerns,   if  any,  associated  with   its  use.  It  is   the responsibility of the user of this standard to establish appro- priate safety and health practices and determine the applica- bility  of  regulatory  limitations  prior  to  use.  For  specific precautionary statements see Sections 5 and 7.

1.6.1   When   the   installation   or   use   of   radiant  barrier materials, accessories, and systems has the potential to pose safety or health problems, the manufacturer shall provide the user  appropriate  current  information  regarding  any  known problems associated with the use of the product of the company and shall also specify protective measures.

2.  Referenced Documents

2.1  ASTM Standards:2

C168Terminology Relating to Thermal Insulation

C1313Specification for Sheet Radiant Barriers for Building Construction Applications

2.2  NFPA Standards:3

NFPA 54National Fuel Gas Code

NFPA 211Standard for Chimneys, Fireplaces and Vents

2.3  Other Document:4

CPSCProduct Safety Fact Sheet No. 18 “The Home Elec- trical System”

3.  Terminology

3.1  Definitions—For  definitions   of  terms  used  in  this practice, refer to Terminology C168.

3.2  Definitions of Terms Specific to This Standard:

3.2.1  applicator,  n—person  or persons  who  apply radiant barrier materials in buildings.

3.2.2  conditioned space, n—any space in a building that is served by a heating or cooling system.

 

2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards volume information, refer to the standard’s Document Summary page on the ASTM website.

3 Available from National Fire Protection Association (NFPA), 1 Batterymarch Park, Quincy, MA 02169-7471, http://www.nfpa.org.

4 Available from U.S. Consumer Product Safety Commission (CPSC), 4330 East West Hwy., Bethesda, MD 20814, http://www.cpsc.gov.

 

 

 

 

Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States

 

 C1744 − 12

 

 

3.2.3  girts, n—typically, 1 or 2× nominal lumber, installed over rafters or trusses, to be used for securing both the RBS and  metal  decking,  which  is  used  on  wall  assemblies  for securing metal siding.

3.2.4  open   air  space,  n—vented  building   cavity   (for example, an open-ended wall or ceiling assembly) or a large conditioned or unconditioned building space.

3.2.4.1  Discussion—A large building space is defined as one whose minimum dimension exceeds 2 ft (0.6 m).

3.2.5 purlins, n—steel or wood structural members that are used to support the buildings primary structural load above the floor.

3.2.6  radiant barrier system, RBS, n—building construction assembly  consisting  of a lowemittance  (0.1  or less)  surface bounded by an open air space on one or both sides.

3.2.6.1  Discussion—Discussion—An  RBS  is  used  for  the sole purpose of limiting heat transfer by radiation into or out of a building assembly. An RBS is not specifically intended to reduce heat transfer by convection or conduction.

3.2.7    subpurlins,  n—secondary  steel  or  wood  structural members that are used primarily to  support the roofing and siding  of a building  are  often  identified  as  “Z purlins,”  “C channel,” “I beams,” or other structural configurations based on cross-sectional appearance.

3.2.8   thermal break, n—low thermal conductivity product such  as  wood  or  polystyrene  used  to  separate  two  higher conductivity products that are most often metal in an effort to reduce heat gain or loss and prevent the potential for conden- sation problems.

4.  Significance and Use

4.1  In this practice it is recognized that effectiveness, safety, and durability of an RBS depends not only on the quality of the materials, but also on proper installation.

4.2  Improper installation of an RBS will reduce the thermal effectiveness, cause fire risks and other unsafe conditions, and promote deterioration of the structure in which it is installed. Improper installations include fires caused by: (1) heat buildup in  recessed  lighting  fixtures,  (2)  deterioration  or  failure  of electrical wiring components,  and  (3) deterioration in wood structures and paint failure as a result of moisture accumula- tion.

4.3  This practice provides direction for the installation of RBS products in a safe and effective manner. Actual conditions in existing buildings vary greatly and care shall be taken to ensure safe and effective installation.

4.4  In this practice, requirements are presented that are both general  and  specific  in  nature  and  practical.  They  are  not intended as specific instructions unless so indicated. The user shall consult the manufacturer for application and installation methods. The requirements in this practice shall be the mini- mum material and installation requirements for RBS.

5.  Pre-Installation Inspection and Preparation

5.1  The applicator shall wear proper clothing and equipment as  specified by the manufacturer  and  shall  follow  all  local,

 

 

state,  and  federal  codes  and  safety  regulations  for  building construction  sites,  for  example,  hard   hats,  safety  goggles respiratory protection, and other safety items.

6.  Safety Precautions

6.1  Pre-Installation  Inspections:  New  and Retrofit  Build- ings:

6.1.1    Inspect  the  roof,  wall,  ceiling,  and  floor  building materials, in both steel and wood structures, to identify areas in which  previous  or  existing  moisture  problems  have  caused paint  peeling,  lumber  warpage,  staining,  rusting,  corrosion, visible fungal growth, rotting, or other structural damage. Do not install the RBS in such areas until the owner/builder has been informed and has certified that these conditions have been corrected and the cause of the condition repaired.

6.1.2   In areas where an RBS is to be installed, components of the electrical system shall be in good condition. When there is reason to believe the electrical system is faulty, do not install RBS in such areas until the owner/builder has been informed and qualified inspection and repair has been accomplished.

NOTE  1—The CPSC Product Safety Fact Sheet No. 18 has identified the following signs of potential electrical deficiencies: lights dimming, fuses blowing, circuit breakers tripping frequently, electrical sparks and glowing from  receptacles,  lights  flickering,  and  cover  plates  on  switches  and outlets that are warm or hot to the touch.

6.1.3  In areas where an RBS is to be installed, the applicator shall locate and plan for installation around ventilation open- ings. The applicator shall not install RBS that will obstruct or block  existing  ventilation  openings,   such  as  gable  ends, dormers, ridge, off ridge, soffit vents, or any others.

6.2  Preparations:

6.2.1  All electrical wiring at, or near, radiant barrier mate- rial attachment surfaces shall be either moved, or protected, to ensure that fasteners used to install the radiant barrier material will not contact the electrical wiring system.

6.2.2  When   soffit   ventilation   exists   in   wood   frame construction,  and  new  or  existing  ceiling  insulation  will be compromised by the installation of an RBS, vent baffles shall be installed at the soffits.

7.  Installation Guidelines

7.1  Material Handling:

7.1.1  The radiant barrier material shall be handled in accor- dance with the manufacturer’s instructions, shall be kept dry, and shall not be in contact with the ground or sources of water.

7.1.2  The  radiant  barrier  material  shall  not  be  placed  in contact with corrosive building materials.

7.2  Performance  Considerations:

7.2.1  The performance of the RBS depends on adherence to manufacturer’s  specifications. Manufacturer’s installation in- structions and all applicable building codes shall be followed. The  manufacturer   shall  provide  the  product  information sheet(s) that specify the product’s intended use(s), application method(s), health and safety requirements, and material prop- erties per Specification C1313.

7.2.2  The  performance  of  the  RBS  is  dependent  on  the presence  of an  open  airspace  adjacent  to  at  least  one  low- emittance surface.

 

 C1744 − 12

 

 

7.2.3  The performance  of the  RBS  will be  adversely  af- fected  by  foreign  materials  on  the  low-emittance  surface. Before installation, foreign materials shall be removed using manufacturer’s  instructions,  taking  care  not  to  damage  the radiant barrier material.

7.2.4  The performance of a radiant barrier will be reduced by a corrosive environment. In some instances, severe pollut- ants react with the low-emittance surface causing an increase in the emittance of the material. When such conditions exist, the owner/builder shall be informed that these conditions have the potential to result in material degradation and a decrease in RBS performance.

7.2.5  In some instances, the performance of a radiant barrier will  be  reduced  by  the  presence  of  moisture  on  the  low- emittance surface. Such conditions are potentially temporary or long term and the manufacturer shall be consulted to determine the applicability of RBS when these conditions are expected to

occur.

7.2.6  The performance  of the  RBS  will be  adversely  af- fected  by  the  accumulation  of  dust  over  time  on  the  low- emittance surface. RBS shall be installed to avoid the settle- ment  of  dust  on  the  radiant  barrier  surface.  Dust  is  not  a concern on a downward facing RBS.

7.2.7  Damaged areas will result in loss of performance and shall be repaired in  accordance  with the manufacturer’s in- structions.

7.3  Precautions:

7.3.1  In areas in which radiant barrier materials are to be installed, the applicator shall provide clearance around lighting fixtures, motors, fans, blowers, heaters, flues, chimneys, and other heat-producing electrical and mechanical devices.

7.3.1.1  The  applicator  shall  provide  3-in.  (75-mm)  mini- mum clearance around all sides of recessed lighting fixtures unless  such  fixtures  are  approved  for  installation  in  direct contact  with radiant barrier  materials.  Such  fixtures  include fixture   wiring   compartments,   ballasts,   and   other   heat- producing devices. These devices shall not be covered unless they are specifically approved for operation when covered.

7.3.1.2  The  applicator  shall  provide  the  minimum  clear- ances specified in NFPA 54. Provide a 2-in. (50-mm) minimum clearance from the outside face of the masonry around masonry chimneys  or  masonry  enclosing  a  flue.  For  vents,  vent connectors, and chimneys other than masonry, provide mini- mum clearances as specified in NAPA 211.

7.3.1.3  The operative material of most RBS is a metallic foil or vapor deposition of a metal on a substrate. Therefore, there is  a  potential   for  radiant  barrier   materials  to  provide   an extremely high resistance to water vapor transmission. Radiant barriers  shall  not  be  installed  so  as  to  lead  to  moisture accumulation and deterioration in the structure. Some radiant barriers are produced to provide low resistance to water vapor transmission. High vapor permeable house wraps and perfo- rated products are examples.

7.3.1.4  In wood or steel framed buildings (new or retreofit), a perforated radiant barrier shall always be used when insula- tion  is  installed  (warm-winter  side),  such  as  in  the  roof  or sidewall installations (Fig. 9), in direct contact with the radiant barrier (cold-winter side). When the radiant barrier is below, or

 

 

next to, an unfaced insulation, in the wall or roof (warm-winter side), a nonperforated radiant barrier shall be used.

7.3.1.5  Regardless of construction type, all radiant barrier materials that are installed with the low-emittance material(s) in direct contact with other metals  shall be  separated by an acceptable thermal break.

7.4  Installation Requirements:

7.4.1  Determine that the RBS material and installation meet the following criteria:

7.4.1.1  Testing and certification—The materials  shall meet all the requirements of Specification C1313 as well as comply with all certification and codes governing the use and installa- tion of radiant barriers.

7.4.1.2  Ventilation—In  all  installation  methods, regardless of the type  of framing  or roofing, materials,  or methods  of installation, inspect all ventilation openings and pathways to be sure  they  are  not  blocked  by  the  installation  of  the  RBS systems.

7.4.1.3  Venting ratio—Typically, a minimum net-free venti- lation of not less than 1 ft2  (0.09 m2) of vent area for each 150 ft2  (14 m2) of floor area (ground level only) be used in both new and retrofit construction whenever practical.

Installation

7.5  The installer or applicator shall install the RBS accord- ing to the manufacturer’s installation guidelines. In addition, the following minimum guideline shall be used when installing an RBS in specific areas of the structure such as:

7.5.1   Wood frame buildings with wood roof decks—There are various methods of installing an RBS:

7.5.1.1  Factory  applied  (laminated)  or  field-applied  RBS (stapled) to the underside of the roof deck facing towards the interior (Fig. 1). A perforated (vapor permeable) RBS is always required for this type of installation. A single- or double-sided radiant  barrier  material  shall  be  used  in  the  deck-applied installation, as long as a low-emittance surface (dull or shiny) faces downward;

7.5.1.2  Draped over the rafters or trusses (top chord) before sheeting the roof (Fig. 2);

7.5.1.3  Installed between the rafters  or top  chords  of the trusses (Fig. 3);

7.5.1.4  Secured to the bottom surface of the rafters or truss (top chord) (Fig. 4); and

7.5.1.5  Shall maintain a minimum 11⁄2-in. (3.8-cm) airspace at the center of the truss/rafter span between the radiant barrier surface and the underside of the roof deck in installations (b) through (d), and a perforated radiant barrier is not required in these installations (Figs. 2-4). Gable end walls, division walls, and all other vertical surfaces above the ceiling insulation, such as in offices and retail building  spaces,  shall be covered by either  a  single-  or  double-sided  radiant  barrier,  perforated (vapor permeable) or not (non vapor permeable), installed with a  low-emittance  surface  facing  the  ceiling  cavity  for  visual inspection purposes regardless of construction materials (Fig. 7).

7.5.2   Wood frame  buildings  with  a  metal  roof  (without oriented strand board (OSB) or plywood sheathing beneath)— There are various methods of installing an RBS:

 

 C1744 − 12

 

RADIANT BARRIER INSTALLATIONS

 

 

RBS Legend

 

 

FIG. 1

 

 

FIG. 2

 

 

FIG. 3

 

 

FIG. 4

 

 

FIG. 5

 

 

 

7.5.2.1   Draped over the rafters, trusses (top chord), or girts before  applying  metal  roofing  as  long  as  there  is  a  proper thermal  break,  such  as  polystyrene  or  wood,  between  the bottom of the metal roof and the top surface of the RBS to prevent the potential for condensation at metal-to-metal points of contact in conditioned buildings (Fig. 8);

7.5.2.2  Installed between the rafters  or top  chords  of the trusses (Fig. 3);

7.5.2.3  Secured to the bottom surface of the rafters or truss (top chord) (Fig. 4); and

 

 

7.5.2.4  Shall maintain a minimum 11⁄2-in. (3.8-cm) airspace at the center of the truss/rafter span between the radiant barrier surface and the underside of the metal roof in installations (b) and (c). A perforated radiant barrier is not required in these installations.

NOTE  2—In retrofit and new construction, secure a perforated radiant barrier directly to the underside portion of the roof deck over the eave or soffit so that the barrier’s coverage extends at least 3 in. (7.6 cm) beyond the top plate of the sidewall without being in contact with any ceiling insulation once it is installed. In an effort to prevent blockage of eave or

 

 C1744 − 12

 

FIG. 6

 

 

FIG. 7

 

 

FIG. 8

 

 

soffit venting, a total vertical airspace of no less than 31⁄2  in. (9 cm) shall be  maintained between  the  RBS  and  the  top  of the  ceiling  insulation regardless of the installation method.

NOTE 3—In new construction or room additions that include vaulted or cathedral  ceilings,  install   a  perforated  radiant  barrier  with  the  low- emittance surface facing downward towards the interior directly against the underside of the roof deck. When installing the insulation, allow a  1- in. (2.5-cm) minimum space between the top of the insulation and the underside  of the  radiant  barrier.  The  most  efficient  system,  either,  by design  or  retrofit,  is  to  vent  both  the  upper  and  lower  ends  of  these assemblies before the installation of the RBS (Fig. 6).

7.5.2.5  Perforated,  or  nonperforated,  radiant  barriers  are options to cover the subpurlins from the peak of the roof to the base of the sidewalls and end walls at the outside, or inside, of the subpurlins in new construction and the inside face of the subpurlins  in  a  retrofit  installation.  In  both  installations,  a thermal  break  shall  be  used  between  the  radiant  barrier material,  metal  roofing,  subpurlins,  and  metal  exterior  wall coverings to prevent the potential for condensation at metal- to-metal points of contact (Fig. 9).

NOTE  4—This practice does not intend to address all of the various commercial/industrial type building assemblies but rather those that are most commonly installed with radiant barrier products such as block wall buildings  framed  with  either  wood  or  steel  studs,  rafters,  or  trusses. However,  the  principles  of proper  installation  are  incorporated  in  this practice  for  most  buildings   that  there   is  potential  benefit   from  the

 

 

installation of a radiant barrier.

7.5.2.6  Unvented low-slope  roofs—In roof assemblies (flat roofs) that have a pitch of less than 1 in. (2.5 cm) in 12 in. (30.5 cm), do not install radiant barrier unless the high end of the roof has  a ridge  vent  or  other high-end  venting  capable  of evacuating  the  excessive  summer  heat.  Building  structures such  as  these  benefit  more  with  added  insulation,  either reflective or mass, specifically in conditioned buildings.

7.5.2.7   Exterior  crawl  spaces  (wood  frame  buildings)— When  covering  the  underside  of  a  floor  assembly  facing  a crawl space cavity, use a nonperforated product, regardless of whether the floor is insulated (Fig. 5). Proper ventilation of these crawl spaces is very important. In this installation, the RBS  is  also  a  vapor  retarder  and  it  shall  always  be  a nonperforated  product. All  seams  and  penetrations  shall  be properly sealed and the crawl space vented to meet necessary code requirements. To prevent damage to the insulation and structure the humidity level in crawl spaces must be maintained below a level that creates a condition for condensation to occur on the crawlspace surfaces. Treatments to prevent crawl space condensation include, but are not limited to: (1) Sealing the interface between the ground and the crawl space walls and

 

 C1744 − 12

 

FIG. 9

 

 

floor; (2) Venting the crawl space to the outside climate, when humidity conditions require.

7.5.2.8   Sidewalls   and   basement   walls   (wood  frame buildings)—Use a perforated radiant RBS on these assemblies only when the wall is not insulated or otherwise covered. Once the wall is covered and not vented, this assembly becomes a reflective insulation system, not a radiant barrier. Consult the manufacturer’s instructions for installing reflective insulation.

7.5.3  Steel framed  buildings  with  a  metal  roof—Typical  construction  of  this  type  of  building   structure  includes   a  corrugated or standing seam steel roof mounted on subpurlins  of numerous designs including  “Z” purlins,  “I” beams,  “C” channel, or various other types of structural steel. The subpur-  lins are attached to a steel purlin that is most commonly an “I” beam  of  some  configuration  that  is  typically   designed  to  support the entire wall and roof loads.

7.6  Post-Installation Inspection:

 

 

 

7.6.1  Ensure that the proper amount of radiant barrier has been  installed  to  achieve  the  greatest  amount  of  protection from heat gain or loss according to the area covered such as: roofs, attics, ceilings, walls, floors, and crawl spaces.

7.6.2  Ensure that the RBS material does not restrict air flow in, out, around, or over exhaust and inlet venting.

7.6.3  The  applicator  shall  provide  a  signed  and  dated statement to the owner/builder describing the RBS installation, the radiant barrier material installed in accordance with Prac- tice C1744, and the area covered.

8.  Keywords

8.1  aluminum  foil;  division  walls;  gable  ends;  low  emit- tance; installation practices; low-slope roofs; metallic deposit; radiant barrier; radiant barrier system; RBS; thermal breaks; vapor retarder; venting ratio

 

ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard.    Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility.

This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn.   Your comments are invited either for revision of this standard or for additional standards and should be addressed toASTM International Headquarters.   Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend.   If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, at the address shown below.

This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.    Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the above address  or  at  610-832-9585  (phone),   610-832-9555  (fax),   or  service@astm.org   (e-mail);  or  through   the  ASTM  website (www.astm.org).  Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http://www.copyright.com/