ASTM E661-22

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Designation: E661 − 03 (Reapproved 2015) E661 − 22
Standard Test Method for
Performance of Wood and Wood-Based Floor and Roof
Sheathing Under Concentrated Static and Impact Loads
This standard is issued under the fixed designation E661; 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 (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—Units information was editorially corrected in March 2015.
INTRODUCTION
During construction and occupancy of a building, floor and roof sheathing are subjected to
concentrated loads that frequently govern the thickness required. Static loads may simulate either foot
traffic, or loads from fixtures, when applied through loading disks of appropriate size. Impact loads
will occur during construction and also in service.
Roof sheathing and subflooring are likely to be critical in strength or stiffness, or both, under foot
traffic and construction loads, while single-layer floors are generally critical under fixture loads, foot
traffic, and in-service impact loads. Subfloors, like single floors, must also support fixture loads, but
they will have an additional layer of material, such as underlayment above, which will help to
distribute concentrated loads.
1. Scope
1.1 This test method covers procedures for determining the resistance to deflection and damage of floor and roof sheathing used
in site-built construction subjected to concentrated static loads as well as impact loads from nonrigid blunt objects. It is applicable
to wood and wood-based panels and boards, but is not intended to cover profiled metal decks, nor precast or cast-in-place slabs.
Surface indentation is not evaluated separately from deflection.
1.2 Three applications are covered: roof sheathing, subfloors, and single floors. Roof sheathing is tested in both a dry and a wet
condition, while subfloors and single floors are both tested in a dry condition, as well as a condition of having dried out after being
wet. These moisture conditions are those commonly experienced with site-built construction.
NOTE 1—Where it is anticipated that sheathing will be subjected only to dry conditions during construction and use, or else to greater moisture exposure
than is indicated in 7.3.2, the corresponding exposure conditions may be modified by agreement between the interested parties. For example, shop-built
construction may be tested dry only, although the possibility of exposure to high humidity or leaks and flooding during use should be considered.
1.3 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.
1.4 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 appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
This test method is under the jurisdiction of ASTM Committee E06 on Performance of Buildings and is the direct responsibility of Subcommittee E06.11 on Horizontal
and Vertical Structures/Structural Performance of Completed Structures.
Current edition approved March 1, 2015Oct. 1, 2022. Published March 2015October 2022. Originally approved in 1978. Last previous edition approved in 20092015 as
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E661 – 03 (2009).(2015) . DOI: 10.1520/E0661-03R15E01.10.1520/E0661-22.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D1517 Terminology Relating to Leather
E575 Practice for Reporting Data from Structural Tests of Building Constructions, Elements, Connections, and Assemblies
E631 Terminology of Building Constructions
2.2 Other Standards:Standard:
Fed. Spec. V-T-291E(1)Fed. Spec. A-A-50197A Linen, Thread
3. Terminology
3.1 See Terminology E631 for terms related to this standard.
4. Summary of Test Method
4.1 Roof and floor sheathing specimens are subjected to concentrated loads applied through a 3-in. (76-mm)3 in. (76 mm) or a
1-in. (25-mm)1 in. (25 mm) diameter loading disk, depending on the intended use and the properties to be evaluated. They are also
subjected to the impact of a shot-filled drop bag. Specimens are tested in a horizontal position, mounted on fully supported framing
members and with loads applied to the top surface near an edge, or at a location determined to be more vulnerable. Any support
framing may be used that is representative of the anticipated service, as the framing is not considered a major test variable.
5. Significance and Use
5.1 The procedures outlined will provide data that can be used to evaluate the structural performance, under concentrated loads,
of roof and floor sheathing, separate from the effects of the framing, under simulated conditions representative of those in actual
service.
5.2 The procedures are intended to be applied to roof or floor sheathing materials installed directly to framing. They are not
intended for the evaluation of the framed assembly as a whole.
6. Apparatus
6.1 Concentrated Load—The apparatus for the concentrated load test shall conform to the following requirements (see Fig. 1):
6.1.1 Supports—The framing members shall be supported in order not to deflect under the applied loads. The support system shall
include provisions for rigidly restraining the ends of the framing members, as with blocking and clamps, to prevent rotation or
vertical movement during testing.
6.1.2 Loading Device—Any convenient means may be used for applying a compressive load up to ultimate, and for measuring
the load within 61 % accuracy. Load shall be applied through a ball-and-socket joint to assure even application.
6.1.3 Loading Disks—Two steel disks are required, one having a diameter of 1 in. (25 mm), representing a concentrated load, and
one of 3 in. (76 mm) representing foot traffic, each with a thickness of at least 0.50 in. (13 mm). The edge of the loading disk
contacting the test specimen shall be rounded to a radius not exceeding 0.06 in. (1.5 mm).
6.1.4 Deflection Gage, mounted on a rigid tripod whose legs rest on the sheathing immediately above the framing members that
are adjacent to the load point (Fig. 1). The deflection gage should have a range exceeding the maximum anticipated deflection, have
a maximum error of 61 %, and be graduated to 0.001 in. (0.02 mm).
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volume information, refer to the standard’sstandard’s Document Summary page on the ASTM website.
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FIG. 1 Concentrated Static Load Apparatus
6.2 Impact Load—The apparatus for the impact load test shall conform to the requirements of 6.1.1 – 6.1.4. In addition, the
following equipment shall be used:
6.2.1 Drop Bag—The bag shall be constructed as in 6.2.1.1 – 6.2.1.3 (see Fig. 2).
6.2.1.1 Leather—The leather used in construction of the bag shall be harness leather (oak tanned from packer hides) or latigo
leather (alum and vegetable tanned), or both. It shall be selected from a back or a side to contain enough area of the required
thickness. Leather thickness shall be expressed in ounces (1 oz = ⁄64 in. (0.4 mm)). The above terms are explained in Terminology
D1517.
6.2.1.2 Thread—Thread used to fabricate the bag shall be linen, of four or more plies, meeting the requirements for Type B,II,
Class 1 or 2, of Fed. Spec. V-T-291E(1).Fed. Spec. A-A-50197A.
6.2.1.3 Fabrication—The bag shall be 28 in. (710 mm) high by 29 in. (735 mm) in circumference, with a sidewall of 8-oz8 oz
leather ⁄8 in. in. (3 mm) thick. The vertical edges shall be sewn together flesh side out and the seam shall be reinforced with a
piece of 8-oz8 oz leather overlapping ⁄8 in. (9 mm) on each side. The side shall then be turned hair side out and sewn to the bottom.
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The base (bottom disk) shall be 99 in. to 10 ⁄2 in. (230(230 mm to 265 mm) in diameter of 12-oz12 oz leather ⁄16 in. in. (5 mm)
thick. The seam attaching the sidewall to the base shall be ⁄4 in. (6 mm) from the edge of the base. Two rows of stitching shall
be used for the vertical sidewall seam and the seam attaching the sidewall to the base.
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(1) The strap to hoist the bag shall be made from 8-oz8 oz leather ⁄8 in. (3 mm) thick by ⁄8 in. (16 mm) wide by 24 in. (610
mm) long. The strap shall be passed through holes, diametrically opposite, in the sidewalls 1 ⁄2 in. in. (40 mm) from the top of
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(1) Leather —Use harness leather (oak-tanned from packer hides) or latigo leather (alum and vegetable tanned) (see Terminology D1517 for definitions of terms) (1-oz
leather = ⁄64 in. (0.4 mm) thick).
(1) Leather—Use harness leather (oak-tanned from packer hides) or latigo leather (alum and vegetable tanned) (see
Terminology D1517 for definitions of terms) (1 oz leather = ⁄64 in. (0.4 mm) thick).
(2) Thread—Use linen thread (minimum four-ply) in accordance with Fed. Spec. A-A-50197A, Type II, Class 1 or 2.
Double-stitch sidewall seam and seam attaching sidewall to base.
(3) Metal Shot—Use shot (0.039 in. to 0.138 in. (1 mm to 3.5 mm) diameter). Fill bag with shot and cover with two layers of
3 in. (76 mm) foam rubber. Adjust total weight of assembly to 30 lb (13.6 kg) 6 ⁄2 %, or more, when specified (see 6.2.1.4).
(2) Thread—Use linen thread (minimum four-ply) in accordance with Fed. Spec. V-T-291E(1), Type B, Class 1 or 2. Double-stitch sidewall seam and seam attaching
sidewall to base.
(3) Metal Shot—Use shot (0.039 to 0.138-in. (1 to 3.5-mm) diameter). Fill bag with shot and cover with two layers of 3-in. (76-mm) foam rubber. Adjust total weight of
assembly to 30 lb (13.6 kg) 6 ⁄2 %, or more, when specified (see 6.2.1.4).
FIG. 2 Leather Drop Bag Assembly
the wall. These holes shall be reinforced with pieces of 8-oz8 oz leather 3 in. (76 mm) square. The leather strap shall be passed
twice through a 2-in. (50-mm)2 in. (50 mm) diameter lifting ring and the ends fastened by sewing, riveting, or by use of a buckle.
(2) To avoid excessive stretching of the leather sidewall or failure of the vertical seam, a sleeve, made from 12-oz12 oz leather,
of the same type as the base of the bag, shall be fitted to slip tightly over the lower portion of the bag. This sleeve should be 9 ⁄8
in. (250 mm) high.
6.2.1.4 Shot—The bag shall be loosely filled with metal shot or pellets with diameters of 0.0390.039 in. to 0.138 in. (1(1 mm to
3.5 mm). Two layers of 3-in. (76-mm)3 in. (76 mm) thick foam rubber or similar padding shall be placed over the metal shot to
prevent spillage during testing. Adjust the total weight of the drop bag and metal shot to the weight specified in Table 1, 6 ⁄2 %.
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TABLE 1 Drop Bag Weights for Impact Load Tests
Total Weight of Drop Bag
Sheathing Span, S
(Including Shot), lb (kg)
S # 24 in. (610 mm) 30 (13.6)
24 in. (610 mm) < S # 48 in. (1220 mm) 60 (27.3)
A
S > 48 in. (1220 mm)
A
See 6.2.1.4.
This value shall be verified before impact tests are conducted. For spans greater than 48 in. (1220 mm), the weight of the drop
bag shall be as agreed upon between the interested parties.
6.2.2 Measuring Rod—A measuring rod, graduated in 6-in. (152-mm)6 in. (152 mm) increments and equipped with a sliding
pointer, shall be used to measure the drop height of the bag.
7. Test Specimens
7.1 Select specimens that are representative of the product being evaluated, both in accordance with the inherent structural
properties, including density, and in accordance with the thickness and thickness tolerances characteristic of the product. Unless
otherwise specified, the number of tests shall be such as to develop the desired confidence level for each property measured, but
conduct at least ten tests as a minimum for each test condition evaluated.
NOTE 2—A specimen can usually be made from a single panel, or assembled from a number of boards (see Figs. 3 and 4).
7.2 Specimen Size:
7.2.1 Length—The specimen length perpendicular to the main framing members shall conform to the center-to-center spacing, S,
anticipated in service (Figs. 3 and 4). Where sheathing is continuous over more than one span, its length shall be equal to the
minimum number of spans permitted or recommended for the product used and its intended application, multiplied by the
center-to-center spacing of the framing members.
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