1、 The following commercial specification is an original Parachute Industry Association specification. PERMANENCE OF SET AND SHRINKAGE IN PARACHUTE FABRICS (BOILED WATER TEST METHOD) The Parachute Industry Association makes this document available for use by Industry and Government organizations that
2、wish to apply this specification to their products. 1. SCOPE 1.1 This method is intended for determining the percent shrinkage, air permeability and thickness of parachute fabrics. 2. TEST SPECIMEN 2.1 Specimens. Two 20 inch square specimens of the cloth shall be prepared. 3. NUMBER OF DETERMINATION
3、S 3.1 Unless otherwise specified in the procurement document, two specimens shall be tested from each sample unit. 4. APPARATUS 4.1 A steel vat/tank large enough to allow specimens to be suspended freely in boiling water for 15 minutes. The specimens shall not come in contact with the bottom of the
4、vat/tank or the heat source. 4.2 A rod long enough to rest on the top of the vat/tank is used to suspend the specimen into the tank utilizing twine or non-rusting wire. A metal frame can also be used instead of the rod and twine set-up. Note: Each specimen requires a separate holder while testing. 4
5、.3 The water in the steel vat/tank shall be heated with a heated jacket, a submersible electric water heater and/or live steam with pre-drilled holes to control the flow of steam into the water. DISTRIBUTION STATEMENT: All Rights Reserved. No Part of this publication may be reproduced without prior
6、written permission from Parachute Industry Association. Additional copies may be purchased on-line from PIA Specifications and Products at: . PIA-TEST METHOD-503A 27 October 2014 Copyright Protected: Do Not Copy!PIA-TEST METHOD-503A 4.4 A rod 1/4” by 21-22 inches long shall be used to weight the bot
7、tom of the specimen loop. The weight shall be 44.5 to 47.5 grams. 4.5 Horizontal screens shall be used to dry the specimens after testing. 4.6 A 20” x 20” and an 18” x 18” template shall be used to mark the specimen sizes for testing. An AATCC Shrinkage Scale (AATCC Part Number 8375) can be used as
8、an alternate method in place of the 18” x 18” template for marking the specimens to determine the shrinkage after Permanence of Set Test. 5. PROCEDURE 5.1 Testing of specimens. Unless otherwise specified in the procurement document, testing shall be performed under standard conditions as specified i
9、n ASTM D 1776. 5.2 Preparation and testing of the specimens before Permanence of Set Test. After a minimum of 4 hours of conditioning (until the specimens reach equilibrium), use a template and indelible ink marker and mark an 18” square on each specimen for shrinkage testing. The specimens shall be
10、 subjected to the air permeability tests in accordance with ASTM D 737 (see paragraph 9 for “conditioning” of ASTM D 737) and the thickness shall be tested in accordance with ASTM D 1777. 5.2.1 The specimens shall be prepared by stapling or tacking the opposite sides of the specimen together to form
11、 a loop or “skein”. One of the specimens will be prepared so that the warp yarns are parallel to the edges of the loop and the second specimen so that the fill yarns are parallel to the edges. 5.2.2 The specimens shall be attached to a rod which will rest on the top of the vat/tank using a twine or
12、non-rusting wire. The wire/twine must be long enough to keep the specimen submerged in the water for the duration of the test but not so long that the specimen touches the bottom of the steel vat/tank. 5.2.3 A rod, 1/4 inch x 21-22 inches long, solid aluminum with a weight of 44.5 to 47.5 grams is p
13、laced in the bottom of the specimen loops to prevent the fabric from floating to the top of the water in the steel vat/tank. 5.2.4 The specimens are placed in the steel vat/tank containing water heated to 210 2F for 15 minutes. The water level in the steel vat shall be five inches from the top of th
14、e vat/tank. The specimen must be submerged in the water controlled within the temperature range for the entire 15 minutes. 5.2.5 Testing shall be performed in pairs-one warp and one fill. The specimens shall be suspended freely in the water and after the 15 minutes removed from the bath and allowed
15、to drain. 5.2.6 The staples/tacks shall be removed from the specimens and the specimens shall be placed on a horizontal screen to air dry. Page 2 of 3 Copyright Protected: Do Not Copy!PIA-TEST METHOD-503A 5.2.7 After the specimens are thoroughly dried they shall be conditioned in accordance with AST
16、M D 1776. 6. REPORT 6.1 Shrinkage. The distance between each of the 18 inch marks on the square shall be remeasured with a ruler to the nearest 0.01 inches in six places, three in the warp and three in the fill, and the average is reported. The percentage of shrinkage shall be reported as follows: W
17、O- WF x 100 = Percent Shrinkage WONote: AATCC Shrinkage Scale (see 4.6) can also be used. WOis the initial width and WF is the corresponding final width. Report the warp and filling averages. The shrinkage shall not exceed specification requirements for each style, both in the warp and filling direc
18、tions. 6.2 Air permeability. If required, the air permeability shall be remeasured in accordance with ASTM D 737 and shall not exceed specification requirements for each style. 6.3 Fabric thickness. If required, the thickness shall be remeasured in accordance with ASTM D 1777 and shall not exceed sp
19、ecification requirements for each style. 7. NOTES 7.1 Sampling of bath. A sample of the Permanence of Set bath should be taken for monitoring pH and the potential effect of pH change on the Permanence of Set air permeability results. This is not a recordable requirement. * Notice: This document is b
20、eing maintained as a commercial specification by the Parachute Industry Association. Orders, inquires and comments should be addressed to PIA, Specification Committee via e-mail at: or to our website at: . Copyright 2014 Parachute Industry Association. Disclaimer: This document is published by the
21、 PIA to provide technical and engineering standards that can be used for reference by all those who may benefit from them. The use of this document is entirely voluntary, and its applicability and suitability for any particular use, including any patent or trademark infringement arising there from, is the sole responsibility of the user. The PIA reviews each technical publication periodically, at which time it may be reaffirmed, revised, or canceled. The PIA invites your written comments and suggestions. Page 3 of 3 Copyright Protected: Do Not Copy!
