TEST PROCEDURE FOR AIR PERMEABILITY TESTING OF RIGID, DISCONTINUOUS

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					                           TESTING APPLICATION STANDARD (TAS) 116-95

             TEST PROCEDURE FOR AIR PERMEABILITY TESTING OF
                   RIGID, DISCONTINUOUS ROOF SYSTEMS

       Scope                                                    2.S   Roof Consultants Institute
                                                                      Glossary of Terms
       1.1   This Protocol covers the determination of the
             air permeability characteristics of arigid,dis-    Terminology & Units
             continuous roof system.
                                                                3.1   Definitions - For definitions of terms in this
       1.2   The test procedures outlined herein shall be             Protocol, refer to Chapter 2 and Section 1513
             used to determine the air pressure difference            of the Florida Building Code, Building and/or
             (DP) and the air volume flow rate (Q) which              the RCI Glossary of Terms. Definitions from
             occur acrosstherigid,discontinuous roof sys-             the Florida Building Code, Building shall take
             tem when the air flow rate into a sealed cham-           precedence.
             ber beneath the system is such that the
             moment incurred on the rigid components            3.2   Units - For conversion of U.S. customary
             within the system is equal to 90% of the                 units to SI units, refer to ASTM E 380.
             restoring moment due to gravity (Mg ) of the
             rigid components.                                  Significance and Use

       1.3   The calculations outlined herein shall be used     4.1   Use of this Protocol is limited to manufactur-
             to determine the air permeability (Cd) for the           ers of rigid, discontinuous roof systems who
                                                                      desire to have their system(s) tested for wind
             system being tested.
                                                                      characteristics in compliance with TAS 108.
                                                                      This limitstheProtocol's use to discontinuous
       1.4   All testing and calculations shall be conduct-
                                                                      roof system in which the unsealed, overlap-
             ed by an approved testing agency and all test
                                                                      ping, rigid components have a length between
             reports, including calculations, shall be signed
                                                                      1.0 and 1.7S feet; an exposed width between
             by a Professional Engineer or Registered Roof
                                                                      0.73 and 1.2S feet; and a thickness not greater
             Consultant.
                                                                      than 1.3 in.
       Referenced Documents
                                                                4.2   The procedures and calculations outlined
                                                                      herein provide a means of determining the air
       2.1   The Florida Building Code, Building.
                                                                      permeability (Cd ) for a rigid, discontinuous
                                                                      roof system. This value shall be listed in the
       2.2   Application Standards
                                                                      system manufacturer's Roof System
             TAS 108 Test Procedure for Wind Tunnel                   Assembly Product Control Approval for refer-
                       Testing of Air Permeable, Rigid,               ence by the Chief Code Compliance Officer to
                       Discontinuous Roof Systems                     determine whether the system is air permeable
                                                                      or air impermeable. The Chief Code
       2.3   The British Standard BS5534 - Appendix                   Compliance Officer may nullify this testing
             A.5.1.                                                   requirement for systems which are generally
             Method of Test for the Air Permeability                  considered air permeable.
             Factor D of Unsealed Small Element Roof
             Assemblies                                         4.3   The test criteria will be based on testing,
                                                                      under the provisions of this Protocol, of rigid,
       2.4 ASTM Standards                                             prepared roof coverings which are generally
           E 380 Excerpts from the Standard Practice                  considered air impermeable (i.e. metal roof
                  for Use of the International System                 systems, and lap sealed, rigid prepared roof
                  of Units (SI) (the Modernized                       coverings). This criteria shall be determined
                  Metric System)                                      by September 1, 1994. Until that date, the

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(TAS) No. 116-95

                 Chief Code Compliance Officer shall judge as             lish appropriate safety and health practices
                 to whether a prepared roof covering is air per-          and determine the applicability of regulatory
                 meable or air impermeable.                               limitations prior to use.

         Apparatus                                                  Apparatus Checks - the following steps shall be
                                                                    conducted prior to any air permeability testing.
         5.1     The pressure from beneath the system shall be
                 generated in a sealed, rectangular plenum          7.1   The pressure tube from the plenum chamber
                 chamber having a depth not less than 2 feet.             to the manometer device shall be checked for
                 The chamber shall be airtight with the excep-            leakage by applying a constant pressure with-
                 tion of an open upper face; a tapping for a              in the tube and clamping it off. Leakage shall
                 pressure tube; and an air inlet pipe. The cham-          be identified by any pressure drop recorded by
                 ber shall be of sufficient dimensions to                 a pressure measuring device. Any pressure
                 receive a wood deck on which the minimum                 tube which exhibits leakage shall be repaired
                 number of rigid components, noted in Section             or replaced.
                 8.5, shall be installed. (See Figure 1,
                 attached.)                                         7.2   The manometer, if utilized, shall be cross-
                                                                          checked against an electrical pressure trans-
         5.2     The pressure tapping, noted in Section 5.1,              ducer.
                 shall be positioned on the chamber so as to
                 avoid direct alignment with the air inlet pipe.    7.3   Airtightness Check
                 The pressure tube shall be connected to a
                 manometer or an electrical pressure transduc-            7.3.1   Close the top of the plenum chamber
                 er to measure the pressure within the chamber                    by attaching and sealing the edges of
                 relative to that outside the chamber. The pres-                  the cover panel so that the plenum
                 sure tapping shall be fully sealed around the                    chamber is air tight with the exception
                 pressure tube.                                                   of the inlet pipe.

         5.3     The air inlet pipe shall be connected to an              7.3.2   Supply air from the electric fan
                 electric fan which is capable of producing a                     through the inlet pipe to induce a pres-
                 continuous air volume flow of 7 ft3/s through                    sure difference between the inside and
                 the air inlet pipe. The connection between the                   outside of the plenum chamber of not
                 air inlet pipe and the chamber shall be fully                    less than 10.5 lbf/ft2.
                 sealed around the perimeter of the air inlet
                 pipe. The air inlet pipe shall be equipped with          7.3.3   If this pressure can be maintained for a
                 an air flow meter capable of measuring an air                    period of 1 minute with an air pressure
                 volume flow rate (Q) of not less than 9.0 ft3/s                  flow rate not greater than 0.2 ft3/s, the
                 and having an accuracy of 0.1 ft3/s.                             airtightness shall be considered satis-
                                                                                  factory.
         5.4     An airtight removable cover panel shall be
                 used to check the air tightness of the plenum
                                                                    Test Specimen
                 chamber, as noted in Section 5.3.
                                                                    8.1   Substrate
         5.5     A weighing device with an accuracy of 0.05 lb
                 shall be used to determine the average mass of
                                                                          8.1.1   The substrate shall consist of APA
                 the rigid components which make up the pre-
                                                                                  32/16 span rated sheathing of 15 / 32 in.
                 pared roof covering.
                                                                                  thickness, attached with 8d common
                                                                                  nails at 6 in. o.c. at panel edges and 12
         Precautions
                                                                                  in. o.c. at intermediate supports, and
                                                                                  an underlayment. The underlayment
         6.1     This Protocol may involve hazardous materi-
                                                                                  shall consist of a No. 30 ASTM D 226,
                 als, operations and equipment. This Protocol
                                                                                  type II asphalt saturated anchor sheet,
                 does not purport to address all of the safety
                                                                                  mechanically attached to the sheathing
                 problems associated with its use. It is the
                                                                                  with approved nails and tin caps
                 responsibility of the user to consult and estab-


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                                                                                                         (TAS) No. 116-95

                     spaced in a 12 in. grid staggered in two                    lished installation instructions.
                     rows in the field and 6 in. o.c. at laps.                   Minimum nails shall be 12 ga. ring
                     Over the anchor sheet, one layer                            shank, hot dipped galvanized roofing
                     ASTM D 249 mineral surfaced cap                             nails. Minimum screws shall be #8
                     sheet shall be applied in a full mopping                    diameter screw fasteners.
                     of ASTM D 312, type IV asphalt. Side
                     laps (if any) shall be 6 in. and head         8.5   Battens (if applicable)
                     laps (if any) shall be 2 in., nailed 12 in.
                     o.c. and 6 in. o.c, respectively.                   8.5.1   Horizontal Batten System

             8.1.2   The substrate, consisting of the wood                       •   Horizontal battens shall be of
                     deck and the underlayment, shall have                           nominal 1in.x 2 in. dimensional lum-
                     3 in. holes spaced 6 in. across its width                       ber and shall be spaced to provide
                     in staggered rows spaced 6 in. along its                        a minimum 3 in. head lap, or to
                     length to allow for airflow into the sys-                       match the interlocking configura-
                     tem.                                                            tion of the component's profile.

             8.1.3   The substrate perimeter shall be com-                       •   Horizontal battens shall be nailed
                     pletely sealed when placed in the                               to the wood test deck at 6 in. o.c.
                     plenum chamber.                                                 using 12 ga. roofing nails.

       8.2   Mortar (if a mortar set tile system assembly)               8.5.2   Counter Batten System

             8.2.1   Mortar mix shall have a Roofing                             •   Vertical battens shall be of
                     Component Product Control Approval                              nominal 1 in. x 4 in. lumber and shall
                     for use with the mortar set tile system                         be spaced 24 in. over the intermedi-
                     and shall be in compliance with TAS                             ate supports (trusses).
                     123.
                                                                                 •   Vertical battens shall be nailed to
             8.2.2   Mortar shall be mixed using the mix-                            the wood test deck at 6 in. o.c. using
                     ing ratio specified in the mortar manu-                         12 ga. roofing nails.
                     facturer's Product Control Approval.
                                                                                 •   Horizontal battens (counter
             8.2.3   Mortar flow shall be determined using                           battens) shall be as noted in
                     a cone penetrometer test, in compli-                            Section 8.5.1, nailedtothe 1 in. x 4 in.
                     ance with ASTM C 780 (Appendix                                  vertical battens using 12 ga.
                     Al), the results of which shall be 21/8                         roofing nails of sufficient length
                     + 1/8 in. (55 ± 3 mm) of penetration.                           to penetrate both battens.

       8.3   Adhesive (if an adhesive set tile system                    8.5.3   If the system being tested is installed
             assembly)                                                           over battens, the battens shall be
                                                                                 installed prior to drilling the 3 in. holes
             8.3.1   Adhesive shall have a Roofing                               noted in Section 8.1.2.
                     Component Product Control Approval
                                                                   8.6   Rigid Components
                     for use with the adhesive set tile sys-
                     tem which is being tested and shall be
                                                                         8.6.1 Rigid components shall meet the size
                     applied in compliance with the provi-
                                                                               requirements listed in Section 4.1.
                     sions set forth in that Approval.
                                                                         8.6.2   Rigid components shall be attached or
       8.4   Fasteners (if applicable)
                                                                                 bonded in compliance with the system
                                                                                 manufacturer's published installation
             8.4.1   Component attachment fasteners (i.e.,                       instructions and the minimum require-
                     nails, screws, tile straps, etc.) shall be                  ments of the Florida Building Code,
                     those recommended in the prepared                           Building. For mechanically attached,
                     roof covering manufacturer's pub-                           direct deck applications, care shall be

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(TAS) No. 116-95

                         taken so as to avoid direct alignment of
                         the fastening line for each course with                                                 where
                         the staggered rows of 3 in. holes in the
                         substrate, noted in Section 7.1.2. For           W =      average component weight (lbf);
                         mortar or adhesive applications, care            m =      average component mass (lbm); and,
                         shall be taken to avoid mortar or adhe-          g =      32.2 ft/s2 = acceleration of
                         sive application over these holes. If                     gravity constant.
                         this is unavoidable due to the configu-
                         ration/spacing of the rigid components           Note: 1 slug = 1 lbf s2/ft
                         within the system, the holes shall be
                         cleared of excess mortar or adhesive             9.1.3   Determine the restoring moment due
                         prior to the material hardening.
                                                                                  to gravity (M g ) from the center of the
                                                                                  exposed area about the head of the
                 8.6.3   The number of rigid components to be                     rigid component using the compo-
                         installed on the substrate, unsealed,                    nent's average weight and the follow-
                         shall be in compliance with Table 1,                     ing equation.
                         below.
                                                                          Mg= W x l                where,
                       TABLE 1
     NUMBER OF COURSES AND NUMBER OF COMPONENTS
                     PER COURSE                                           M g = restoring moment due to gravity
       Component         Minimum Number of Minimum Number per                   (ft-lbf);
         Type                 Courses            Course                   W = average component weight (lbf); and
      Single Lap                  2                   2                   1 = moment arm (ft) (distance from center
Plain Tiles (bonded or            2                   4                         of exposed area to the head of the
mechanically attached)                                                          component)
        Slates                    2                   2
                                                                    9.2   Pressure to Induce Moment (p)
                 8.6.4   In addition to the number of compo-
                         nents listed in Table 1, a sufficient            9.2.1   Determine the upward pressure
                         number of components shall be pro-                       required to induce the restoring
                         vided to cover the perimeter area of the                 moment due to gravity, determined
                         substrate. These components shall be                     above, using the following equation.
                         completely sealed at all laps, front and
                         side joints with approved adhesive.                                                where,

9.       Preliminary Measurements and Calculations
                                                                          p  = pressure required to induct moment
         9.1     Average Mass, Weight and Restoring Moment
                 due to Gravity (Mg)                                           (lbf/ft2);
                                                                          Mg = restoring moment due to gravity
                 9.1.1   Determine the mass of eachrigidcom-                   (ft-lbf);
                         ponent to be installed and calculate the         b  = component cover width (ft);
                         average mass.                                    1o = component exposed length (ft)
                                                                             = total length - headlap dimension; and
                 9.1.2   Determine the average weight of the              1  = moment arm (ft) (distance from
                         rigid components using the average                    center of exposed area to the head of
                         mass and the following equation.                      the component)

                                                                    9.3   Effective Area (a)

                                                                          9.3.1   Determine the effective area (a) (i.e.,
                                                                                  the area having unsealed components)
                                                                                  across which the pressure difference
                                                                                  will occur using the following equa-
                                                                                  tion.

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                                                                                                         (TAS) No. 116-95

            a = Nxbx            lo    where,                   12.   Report

            a    =    effective area (ft2);                          12.1 The final test report shall include the follow­
            N    =    number of unsealed components;                      ing:
            b    =    component cover width (ft); and
            1o   =    component exposed length (ft)                       12.1.1 The type, name, and manufacturer of
                                                                                 the discontinuous roof system and the
                 =    total length - headlap dimension
                                                                                 dimensions of the rigid components
                                                                                 within the system.
10.    Test Procedure
                                                                          12.1.2 A detailed report of the system instal­
       10.1 Position the test specimen in the plenum
                                                                                 lation prepared by a Professional
            chamber, insuring that born the substrate
                                                                                 Engineer or Registered Roof
            perimeter and the perimeter rigid components
                                                                                 Consultant, including a sketch of the
            are completely sealed.
                                                                                 installed system, indicating the sealed
                                                                                 and unsealed components, and the
       10.2 Supply air through the inlet pipe to the
                                                                                 published installation instructions pro­
            plenum chamber, gradually increasing the air­                        vided by the system manufacturer.
            flow until the manometer indicates a pressure
            difference (ΔP) equal to 90% of the pressure
                                                                          12.1.3 Data and calculations for average mass
            (p) determined in Section 9.2.
                                                                                 (m); average weight (W); restoring
       10.3 When the pressure difference (ΔP) reaches                            moment due to gravity (Mg); pressure
            this point, record the pressure difference (ΔP)                      required to induce moment (p); and
            and the air volume flow rate (Q) and gradual­                        effective area (a).
            ly reduce the air supply to zero.
                                                                          12.1.4 Pressure difference (ΔP) and air vol­
       10.4 Repeat this test procedure three times using                         ume flow rate (Q) readings at the point
            the same test specimen. If any evidence of                           when the pressure needed to incur
            damage exists subsequent to any test, con­                           moment is attained.
            struct an additional test specimen for the addi­
            tional test(s).                                               12.1.5 Calculations and results for the air per­
                                                                                 meability (Cd) of the three tests and
11.    Calculations                                                              the average value.

       11.1 Determine the air permeability (Cd) using
            information gathered from preliminary calcu­
            lations, testing procedures and the following
            equation.

                                               where,




                 Cd   =   air permeability (dimensionless);
                 Q    =   air volume flow rate (ft3/s);
                 a    =   effective area (ft2);
                 ΔP   =   pressure difference (lbf/ft2); and
                 ρ    =   density of air = 2.377 x 10-3
                          slugs/ft3

       11.2 Determine the average air permeability for the
            three tests conducted.

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                              FIGURE 1
                   AIR PERMEABILITY TEST APPARATUS




(TAS) 116-95.6                             FLORIDA BUILDING CODE — TEST PROTOCOL HVHZ