ASTM E1307-18

Standard Practice for Surface Preparation and Structural Adhesive Bonding of Precured, Nonmetallic Composite Facings to Structural Core for Flat Shelter Panels

SIGNIFICANCE AND USE
4.1 Durable adhesive bonds of composite laminates can be obtained reliably only through proper selection and careful control of the materials used and the steps in the bonding process. The preparation of the composite laminates to obtain surfaces with appropriate characteristics is a critical step. Improper surface preparation can produce seemingly acceptable bonds that can degrade rapidly with time. This practice describes how properly prepared surfaces can be obtained.  
4.2 The formation of reproducible, durable, adhesive bonds in structural units requires great care in the selection of materials, the preparation of the surfaces of the parts to be bonded, the fit of parts, and the performance of the steps in the bonding process. Experience has shown that adhesive bonding carried out in accordance with this practice produces reproducible bonds.
SCOPE
1.1 This practice covers the materials, processes, and quality controls to be used in the manufacture of durable adhesive bonded, nonmetallic faced, flat sandwich panels for rigid wall relocatable shelters.  
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to inch-pound units that are provided for information only and are not considered standard.  
1.3 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 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.

General Information

• Status: Published
• Publication Date: 30-Sep-2018
• ICS: 79.060.01 - Wood-based panels in general
• Technical Committee: E06 - Performance of Buildings
• Drafting Committee: E06.53 - Materials and Processes for Durable Rigidwall Relocatable Structures

Relations

• Replaces: ASTM E1307-10 - Standard Practice for Surface Preparation and Structural Adhesive Bonding of Precured, Nonmetallic Composite Facings to Structural Core for Flat Shelter Panels
• Effective Date: 01-Oct-2018
• Refers: ASTM E1749-18 - Standard Terminology Relating to Rigid Wall Relocatable Shelters
• Effective Date: 01-Oct-2018
• Refers: ASTM C297/C297M-16 - Standard Test Method for Flatwise Tensile Strength of Sandwich Constructions
• Effective Date: 01-Apr-2016
• Refers: ASTM C297/C297M-15 - Standard Test Method for Flatwise Tensile Strength of Sandwich Constructions
• Effective Date: 01-Apr-2015
• Refers: ASTM E631-15 - Standard Terminology of Building Constructions
• Effective Date: 01-Mar-2015
• Refers: ASTM E631-14 - Standard Terminology of Building Constructions
• Effective Date: 01-Nov-2014
• Refers: ASTM E1749-10 - Standard Terminology Relating to Rigid Wall Relocatable Shelters
• Effective Date: 01-Nov-2010
• Refers: ASTM C297/C297M-04(2010) - Standard Test Method for Flatwise Tensile Strength of Sandwich Constructions
• Effective Date: 01-Oct-2010
• Refers: ASTM E990-09 - Standard Specification for Core-Splice Adhesive for Honeycomb Sandwich Shelter Panels
• Effective Date: 01-Nov-2009
• Refers: ASTM E1091-08 - Standard Specification for Nonmetallic Honeycomb Core for Use in Shelter Panels
• Effective Date: 01-Nov-2008
• Refers: ASTM E865-08 - Standard Specification for Structural Film Adhesives for Honeycomb Sandwich Panels
• Effective Date: 01-Nov-2008
• Refers: ASTM E631-06 - Standard Terminology of Building Constructions
• Effective Date: 01-Jun-2006
• Refers: ASTM E1749-05 - Standard Terminology Relating to Rigid Wall Relocatable Shelters
• Effective Date: 01-Oct-2005
• Refers: ASTM C297/C297M-04 - Standard Test Method for Flatwise Tensile Strength of Sandwich Constructions
• Effective Date: 01-May-2004
• Refers: ASTM E990-04 - Standard Specification for Core-Splice Adhesive for Honeycomb Sandwich Shelter Panels
• Effective Date: 01-Apr-2004

Overview

ASTM E1307-18 - Standard Practice for Surface Preparation and Structural Adhesive Bonding of Precured, Nonmetallic Composite Facings to Structural Core for Flat Shelter Panels - is a critical standard for the manufacturing and quality assurance of sandwich panels used in relocatable shelters. Published by ASTM International, this practice ensures the reliability and durability of adhesive bonds between nonmetallic composite facings and structural cores. Correct surface preparation, material selection, and process control are central to forming adhesive bonds that maintain long-term structural performance under various environmental conditions.

Key Topics

• Surface Preparation: Highlights the vital importance of properly preparing composite surfaces before bonding. Inadequate preparation can lead to bond failure or rapid degradation over time.
• Materials and Adhesives: Specifies requirements for core materials, facings, reinforcements, resin systems, peel ply fabrics, and structural film adhesives, ensuring all components meet design and procurement standards.
• Process Controls and Facilities: Describes environmental and cleanliness requirements for assembly areas, including controlled temperature, humidity, and airborne particle counts to maintain panel integrity.
• Bonding Equipment: Outlines standards for platen press and autoclave operations, including calibration, temperature, and pressure controls essential for reproducible, high-strength adhesive bonds.
• Quality Assurance: Requires comprehensive inspection, marking, traceability, and testing of both materials and finished shelter panels to ensure compliance with performance requirements.
• Testing and Acceptance: Includes processes for flatwise tensile strength testing of process control specimens (per ASTM C297/C297M) and criteria for visual, dimensional, and non-destructive inspection.

Applications

ASTM E1307-18 provides the foundational practice for industries involved in the design, manufacture, and quality assurance of sandwich panels for rigid-wall, relocatable shelters. These panels are integral in:

• Military and Defense Shelters: Used extensively for rapid deployment and protection in harsh environments, meeting stringent U.S. Department of Defense requirements.
• Emergency and Humanitarian Shelters: Providing quick-assembly solutions for disaster response, field hospitals, and temporary housing.
• Mobile and Modular Buildings: Enabling the fabrication of flat panels with high strength-to-weight ratios, suitable for relocation and reuse.
• Industrial Enclosures: Used wherever durable, lightweight, and well-insulated walls are required for equipment protection or clean-room environments.

In each of these applications, durable adhesive bonding and consistent surface preparation are essential for safety, longevity, and performance of the structure.

Related Standards

ASTM E1307-18 references and is complemented by several other important standards:

• ASTM C297/C297M: Test Method for Flatwise Tensile Strength of Sandwich Constructions - for evaluating bonding strength.
• ASTM E631: Terminology of Building Constructions - provides common language for the industry.
• ASTM E865 & E990: Specifications for structural film adhesives and core splice adhesives for honeycomb sandwich structural panels.
• ASTM E1091: Specification for nonmetallic honeycomb core for use in shelter panels.
• FED STD 209: Clean Room and Work Station Requirements - ensures appropriate environmental controls.
• SAE-AMS-S-8802: Sealing Compound for edge sealing in panel assemblies.
• MIL-Handbook 337: Procedures for inspection and testing of adhesive bonded aerospace structures.

Practical Value

Implementing ASTM E1307-18 ensures high-quality, reproducible adhesive bonds in the construction of composite-faced sandwich panels. Manufacturers, defense contractors, and suppliers benefit from:

• Improved Reliability and Safety: Reduces risk of structural failure through rigorous control of materials and processes.
• Compliance and Traceability: Facilitates contractual and regulatory compliance, including Department of Defense requirements.
• Efficient Production: Streamlines procurement, handling, and manufacturing workflows for precision and repeatability.
• Product Performance: Enhances durability and lifespan of shelter panels in demanding environments.

For organizations involved in shelter panel production or procurement, adherence to ASTM E1307-18 is essential for delivering robust, high-performance structures that meet both industry and government expectations.

Keywords: adhesive bonding, composite facing, relocatable shelters, sandwich panels, surface preparation, structural core, ASTM standards, quality assurance, panel construction.

Standards Content (Sample)

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.
Designation: E1307 − 18
Standard Practice for
Surface Preparation and Structural Adhesive Bonding of
Precured, Nonmetallic Composite Facings to Structural
Core for Flat Shelter Panels
This standard is issued under the fixed designation E1307; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope comb Sandwich Structural Panels
E1091Specification for Nonmetallic Honeycomb Core for
1.1 This practice covers the materials, processes, and qual-
Use in Shelter Panels
ity controls to be used in the manufacture of durable adhesive
E1749Terminology Relating to Rigid Wall Relocatable
bonded, nonmetallic faced, flat sandwich panels for rigid wall
Shelters
relocatable shelters.
2.2 Federal Standard:
1.2 The values stated in SI units are to be regarded as
FEDSTD209Clean Room and Work Station Requirements
standard. The values given in parentheses are mathematical
2.3 Society of Automotive Engineers (SAE) Standard:
conversions to inch-pound units that are provided for informa-
SAE-AMS-S-8802 Sealing Compound, Temperature-
tion only and are not considered standard.
Resistant, Integral Fuel Tanks and Fuel Cell Cavities,
1.3 This standard does not purport to address all of the
High-Adhesion
safety concerns, if any, associated with its use. It is the
2.4 Military Handbook:
responsibility of the user of this standard to establish appro-
MIL-Handbook337Adhesive BondedAerospace Structures
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
3. Terminology
1.4 This international standard was developed in accor-
3.1 Definitions:
dance with internationally recognized principles on standard-
3.1.1 For definitions of general terms related to building
ization established in the Decision on Principles for the
construction used in this practice, refer to Terminology E631
Development of International Standards, Guides and Recom-
and for general terms related to rigid wall relocatable shelters,
mendations issued by the World Trade Organization Technical
refer to Terminology E1749.
Barriers to Trade (TBT) Committee.
4. Significance and Use
2. Referenced Documents
4.1 Durable adhesive bonds of composite laminates can be
2.1 ASTM Standards:
obtained reliably only through proper selection and careful
C297/C297MTest Method for Flatwise Tensile Strength of
control of the materials used and the steps in the bonding
Sandwich Constructions
process. The preparation of the composite laminates to obtain
E631Terminology of Building Constructions
surfaces with appropriate characteristics is a critical step.
E865Specification for Structural Film Adhesives for Hon-
Improper surface preparation can produce seemingly accept-
eycomb Sandwich Panels
able bonds that can degrade rapidly with time. This practice
E990Specification for Core-Splice Adhesive for Honey-
describes how properly prepared surfaces can be obtained.
4.2 The formation of reproducible, durable, adhesive bonds
This practice is under the jurisdiction of ASTM Committee E06 on Perfor- in structural units requires great care in the selection of
mance of Buildings and is the direct responsibility of Subcommittee E06.53 on
materials, the preparation of the surfaces of the parts to be
Materials and Processes for Durable Rigidwall Relocatable Structures.
bonded, the fit of parts, and the performance of the steps in the
Current edition approved Oct. 1, 2018. Published November 2018. Originally
approved in 1989. Last previous edition approved in 2010 as E1307–10. DOI:
10.1520/E1307–18.
2 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Available from DLA Document Services, Building 4/D, 700 Robbins Ave.,
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Philadelphia, PA 19111-5094, http://quickserach.dla.mil.
Standards volume information, refer to the standard’s Document Summary page on AvailablefromSAEInternational(SAE),400CommonwealthDr.,Warrendale,
the ASTM website. PA 15096, http://www.sae.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1307 − 18
bonding process. Experience has shown that adhesive bonding the ECA shall be clean, low shed, and free from lint, oil, and
carriedoutinaccordancewiththispracticeproducesreproduc- grease. The use and application of oil, grease, mold release
ible bonds. agents, or other possible contaminants within the ECAshall be
prohibited. The interior, exposed surfaces of the ECAshall be
nonshedding and easily cleaned to minimize dust generation.
5. Materials
Any particle-generating preparations such as removal of peel
5.1 Materials—Materials shall be as specified herein or as
ply, insertion of foam into honeycomb core, or cleaning must
specified in the contract. All materials shall be stored and
be accompanied by filtered vacuum when performed in the
handled in such a manner as to provide protection against
ECA.
degrading environments and mechanical damage.
5.2 Composite Reinforcement and Resin—The composite
7. Equipment
reinforcement and resin shall meet the requirements specified
7.1 Platen Press—Pressure equipment for bonding of shel-
in the procurement document.
ter panels shall be large enough to permit the bonding of the
5.3 Peel Ply Fabric—Anonreuseablepeelplyshallbeused.
total panel in one step. The manufacturer shall provide cali-
Closely woven fabric of nylon, polyester, or glass has been
bration and test data demonstrating that the temperature on the
foundsuitable.Thepeelplyfabricmustbecompatiblewiththe
two facings of press platens during lamination will be equal
manufacturing process.
and uniform within 4% of their nominal temperature. The
5.4 Precured Facings—The facings shall be certified as pressure equipment used for curing the panels shall be capable
complying with the reinforcement, resin binder, resin content, of applying greater than 140 kPa (20 psi) and 150°C (300°F)
and thickness requirements of the procurement document. overtheentirepanelsurface.Platensshallbeflattowithin0.17
Facings shall be free of defects that may adversely affect the mm/m(0.002in./ft).Thepressureequipmentshallbeequipped
structural integrity of the bonded panel. with temperature and pressure recorders and controls that
accurately control heat-up rate, pressure application, dwell
5.5 Core—The core material shall be as specified in Speci-
time, cool down (when required), and pressure removal. The
ficationE1091ortheprocurementdocumentandshallmeetthe
pressure equipment shall also be equipped with suitable
requirements of the applicable document.
devices (for example, caul sheets) that facilitate moving the
5.6 Structural Film Adhesive—The adhesive shall conform
panel layup into the press without misaligning the layup.
to the requirements of Specification E865. It shall be stored in
7.1.1 Calibrations, Temperature, and Pressure Require-
accordance with the manufacturer’s recommendations.
ments and Controls—Gauges shall be calibrated at least every
5.7 Core Splice Adhesive—The core splice adhesive shall six months by an accredited independent laboratory or by the
conform to the requirements of Specification E990. It shall be manufacturer if approved by the purchaser. The latest calibra-
stored in accordance with the manufacturer’s recommenda- tion certificate shall be attached to the equipment near each
tions. gauge.Itshallbedemonstratedthattheactualbondingpressure
is within 10% of the nominal pressure. It shall also be
6. Facilities demonstrated that the average temperatures of the top and
bottom panel facings during the bonding process are equal and
6.1 PanelAssembly LayupArea—Thepanelassemblylayup
uniform to within 4% of the nominal temperature. Thermo-
area is an enclosed, environmentally controlled area (ECA)
couples placed within 150 mm (6 in.) of each corner and at the
that is continuously controlled for temperature, relative
center of each facing shall be used to demonstrate the unifor-
humidity, and concentration of airborne particles. The ECA
mity of the temperature. Compliance of the equipment with
shallbemaintainedatatemperatureof24 66°C(75 610°F)
these requirements shall be verified at intervals not exceeding
andnotmorethan50%relativehumidity.Thetemperatureand
six months. A permanent record of the pressure, time, and
relative humidity shall be recorded continuously.All incoming
temperature measurements during bonding compliance checks
and recirculated air shall be filtered to control airborne par-
shall be maintained. All calibrations must be traceable to the
ticles.Theairhandlingequipmentshallprovideatleastfiveair
National Institute of Standards and Technology (NIST).
changes per hour in the ECA. The filters shall ensure that the
particle count within the ECAwill not exceed 7×10 particles 7.2 Autoclave—The autoclave equipment for bonding shel-
per cubic metre (200000 particles per cubic foot) of size 1 µm ter panels shall be large enough to permit the bonding of entire
and larger. The air pressure differential between the ECA and shelter panel assemblies in one step. The autoclave shall be
adjacent areas shall be monitored continuously and recorded at equipped with vacuum gauges and temperature and pressure
least twice weekly. The air pressure in the ECA shall be recorders that accurately control heat-up rate, pressure
maintainedabovethatofadjacentareasbyaminimumof50Pa application, dwell time, cool down, and pressure removal.
(0.015 in. Hg). The particle count shall be monitored in Vacuum venting facilities shall be provided. The autoclave
accordance with FEDSTD209. The recorders shall be cali- equipment used for curing the panels shall be capable of
brated every six months. The ECA shall be conspicuously applying greater than 140 kPa (20 psi) and 150°C (300°F).
identified at all entrances as “limited access.” Unnecessary The manufacturer shall provide calibration and test data
traffic within the ECA shall not be permitted. Eating and demonstrating that the temperature was maintained within 4%
smoking within the ECA shall not be permitted and the ECA of the nominal temperature and the pressure was maintained
shall be so posted. All material, tools, and equipment used in within 10% of the operating pressure.
E1307 − 18
7.3 Testing Equipment—The supplier shall have available facings and framing members shall be free of contaminants
sufficient testing equipment to ensure that all process control before application of the adhesive. Parts requiring identifica-
specimen preparation and testing required by this practice can
tion shall be marked with inks or methods approved for
beaccomplished.Allcalibrationsoftestequipmentrequiredby
bonding.
this practice shall be traceable to the NIST.
10.4 Preparation of Core—Thecoreshallbecleanedofdust
with dry, oil-free, filtered compressed air or vacuumed prior to
8. Preparation of Composite Facings
delivery to the panel assembly layup area. When honeycomb
8.1 The composite reinforcement, number of plies, resin,
core is used and the cells are filled with plastic foam, the
and cure cycle shall meet the requirements as specified in the
surface of the installed foam shall be at least 1.5 mm ( ⁄16 in.)
shelter specification.
below the surface of the honeycomb on both surfaces, and all
8.2 Peel Ply—A peel ply shall be included as the surface
bonding surfaces shall be free of foam, dust, and contaminants
layerforthesideoftheprecuredskinthatwillbelaterbonded.
by vacuuming. When a panel requires more than one sheet of
The peel ply shall extend past all edges.
core, the seam between pieces shall be spliced so that the
8.3 Peel Ply Removal—Prior to bonding, remove the peel
uniformity of thickness is maintained across the seam. The
ply from the faying surface to provide a clean, high-area
core splicing material must be impermeable to water and serve
surface ideal for bonding. Removal shall be accomplished in
as a barrier to water migration and meet the requirements of
the ECA.
Specification E990. The core splicing method and adhesive
used shall be such that the shear strength of the splice shall be
9. Quality Assurance of Composite Facings
equal to or greater than the core shear strength. Any crushed
9.1 Handling—Parts with the peel ply removed or being
corners and edges of the core sheets shall be repaired and the
removed shall be handled using clean gloves or other methods
sheet resquared prior to splicing and lamination. Where the
to prevent surface contamination.
shelter design requires that all framing members be bonded
simultaneously with panel bonding, the core shall fit into the
9.2 Marking—All processed parts shall be marked with the
date and time of manufacture. If the surface wit
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E1307 − 10 E1307 − 18
Standard Practice for
Surface Preparation and Structural Adhesive Bonding of
Precured, Nonmetallic Composite Facings to Structural
Core for Flat Shelter Panels
This standard is issued under the fixed designation E1307; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope
1.1 This practice covers the materials, processes, and quality controls to be used in the manufacture of durable adhesive bonded,
nonmetallic faced, flat sandwich panels for rigid wall relocatable shelters.
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions
to inch-pound units that are provided for information only and are not considered standard.
1.3 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.
1.4 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:
C297/C297M Test Method for Flatwise Tensile Strength of Sandwich Constructions
E631 Terminology of Building Constructions
E865 Specification for Structural Film Adhesives for Honeycomb Sandwich Panels
E990 Specification for Core-Splice Adhesive for Honeycomb Sandwich Structural Panels
E1091 Specification for Nonmetallic Honeycomb Core for Use in Shelter Panels
E1749
2.2 Federal Standard:
FED STD 209 Clean Room and Work Station Requirements
2.3 Society of Automotive Engineers (SAE) Standard:
SAE-AMS-S-8802 Sealing Compound, Temperature-Resistant, Integral Fuel Tanks and Fuel Cell Cavities, High-Adhesion
2.4 Military Handbook:
MIL-Handbook 337 Adhesive Bonded Aerospace Structures
3. Terminology
3.1 Definitions:
3.1.1 For definitions of general terms related to building construction used in this practice, refer to Terminology E631 and for
general terms related to rigid wall relocatable shelters, refer to Terminology E1749.
This practice is under the jurisdiction of ASTM Committee E06 on Performance of Buildings and is the direct responsibility of Subcommittee E06.53 on Materials and
Processes for Durable Rigidwall Relocatable Structures.
Current edition approved Nov. 1, 2010Oct. 1, 2018. Published December 2010November 2018. Originally approved in 1989. Last previous edition approved in 20052010
as E1307 – 05.E1307–10. DOI: 10.1520/E1307-10.10.1520/E1307–18.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’sstandard’s Document Summary page on the ASTM website.
Available from Standardization Documents Order Desk, DODSSP, Bldg. 4, Section D, DLA Document Services, Building 4/D, 700 Robbins Ave., Philadelphia, PA
19111-5098, http://dodssp.daps.dla.mil.19111-5094, http://quickserach.dla.mil.
Available from SAE International (SAE), 400 Commonwealth Dr., Warrendale, PA 15096-0001,15096, http://www.sae.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1307 − 18
4. Significance and Use
4.1 Durable adhesive bonds of composite laminates can be obtained reliably only through proper selection and careful control
of the materials used and the steps in the bonding process. The preparation of the composite laminates to obtain surfaces with
appropriate characteristics is a critical step. Improper surface preparation can produce seemingly acceptable bonds that can degrade
rapidly with time. This practice describes how properly prepared surfaces can be obtained.
4.2 The formation of reproducible, durable, adhesive bonds in structural units requires great care in the selection of materials,
the preparation of the surfaces of the parts to be bonded, the fit of parts, and the performance of the steps in the bonding process.
Experience has shown that adhesive bonding carried out in accordance with this practice produces reproducible bonds.
5. Materials
5.1 Materials—Materials shall be as specified herein or as specified in the contract. All materials shall be stored and handled
in such a manner as to provide protection against degrading environments and mechanical damage.
5.2 Composite Reinforcement and Resin—The composite reinforcement and resin shall meet the requirements specified in the
procurement document.
5.3 Peel Ply Fabric—A nonreuseable peel ply shall be used. Closely woven fabric of nylon, polyester, or glass has been found
suitable. The peel ply fabric must be compatible with the manufacturing process.
5.4 Precured Facings—The facings shall be certified as complying with the reinforcement, resin binder, resin content, and
thickness requirements of the procurement document. Facings shall be free of defects that may adversely affect the structural
integrity of the bonded panel.
5.5 Core—The core material shall be as specified in Specification E1091 or the procurement document and shall meet the
requirements of the applicable document.
5.6 Structural Film Adhesive—The adhesive shall conform to the requirements of Specification E865. It shall be stored in
accordance with the manufacturer’smanufacturer’s recommendations.
5.7 Core Splice Adhesive—The core splice adhesive shall conform to the requirements of Specification E990. It shall be stored
in accordance with the manufacturer’smanufacturer’s recommendations.
6. Facilities
6.1 Panel Assembly Layup Area—The panel assembly layup area is an enclosed, environmentally controlled area (ECA) that is
continuously controlled for temperature, relative humidity, and concentration of airborne particles. The ECA shall be maintained
at a temperature of 24 6 6°C6 °C (75 6 10°F)10 °F) and not more than 50 % relative humidity. The temperature and relative
humidity shall be recorded continuously. All incoming and recirculated air shall be filtered to control airborne particles. The air
handling equipment shall provide at least five air changes per hour in the ECA. The filters shall ensure that the particle count within
the ECA will not exceed 7 × 10 particles per cubic metre (200 000 particles per cubic foot) of size 1 μm and larger. The air
pressure differential between the ECA and adjacent areas shall be monitored continuously and recorded at least twice weekly. The
air pressure in the ECA shall be maintained above that of adjacent areas by a minimum of 50 Pa (0.015 in. Hg). The particle count
shall be monitored in accordance with FED STD 209. The recorders shall be calibrated every six months. The ECA shall be
conspicuously identified at all entrances as “limited access.” Unnecessary traffic within the ECA shall not be permitted. Eating and
smoking within the ECA shall not be permitted and the ECA shall be so posted. All material, tools, and equipment used in the ECA
shall be clean, low shed, and free from lint, oil, and grease. The use and application of oil, grease, mold release agents, or other
possible contaminants within the ECA shall be prohibited. The interior, exposed surfaces of the ECA shall be nonshedding and
easily cleaned to minimize dust generation. Any particle-generating preparations such as removal of peel ply, insertion of foam into
honeycomb core, or cleaning must be accompanied by filtered vacuum when performed in the ECA.
7. Equipment
7.1 Platen Press—Pressure equipment for bonding of shelter panels shall be large enough to permit the bonding of the total
panel in one step. The manufacturer shall provide calibration and test data demonstrating that the temperature on the two facings
of press platens during lamination will be equal and uniform within 4 % of their nominal temperature. The pressure equipment used
for curing the panels shall be capable of applying greater than 140 kPa (20 psi) and 150°C (300°F)150 °C (300 °F) over the entire
panel surface. Platens shall be flat to within 0.17 mm/m (0.002 in./ft). The pressure equipment shall be equipped with temperature
and pressure recorders and controls that accurately control heat-up rate, pressure application, dwell time, cool down (when
required), and pressure removal. The pressure equipment shall also be equipped with suitable devices (for example, caul sheets)
that facilitate moving the panel layup into the press without misaligning the layup.
7.1.1 Calibrations, Temperature, and Pressure Requirements and Controls—GagesGauges shall be calibrated at least every six
months by an accredited independent laboratory or by the manufacturer if approved by the purchaser. The latest calibration
certificate shall be attached to the equipment near each gage.gauge. It shall be demonstrated that the actual bonding pressure is
E1307 − 18
within 10 % of the nominal pressure. It shall also be demonstrated that the average temperatures of the top and bottom panel
facings during the bonding process are equal and uniform to within 4 % of the nominal temperature. Thermocouples placed within
150 mm (6 in.) of each corner and at the center of each facing shall be used to demonstrate the uniformity of the temperature.
Compliance of the equipment with these requirements shall be verified at intervals not exceeding six months. A permanent record
of the pressure, time, and temperature measurements during bonding compliance checks shall be maintained. All calibrations must
be traceable to the National Institute of Standards and Technology (NIST).
7.2 Autoclave—The autoclave equipment for bonding shelter panels shall be large enough to permit the bonding of entire shelter
panel assemblies in one step. The autoclave shall be equipped with vacuum gagesgauges and temperature and pressure recorders
that accurately control heat-up rate, pressure application, dwell time, cool down, and pressure removal. Vacuum venting facilities
shall be provided. The autoclave equipment used for curing the panels shall be capable of applying greater than 140 kPa (20 psi)
and 150°C (300°F).150 °C (300 °F). The manufacturer shall provide calibration and test data demonstrating that the temperature
was maintained within 4 % of the nominal temperature and the pressure was maintained within 10 % of the operating pressure.
7.3 Testing Equipment—The supplier shall have available sufficient testing equipment to ensure that all process control
specimen preparation and testing required by this practice can be accomplished. All calibrations of test equipment required by this
practice shall be traceable to the NIST.
8. Preparation of Composite Facings
8.1 The composite reinforcement, number of plies, resin, and cure cycle shall meet the requirements as specified in the shelter
specification.
8.2 Peel Ply—A peel ply shall be included as the surface layer for the side of the precured skin that will be later bonded. The
peel ply shall extend past all edges.
8.3 Peel Ply Removal—Prior to bonding, remove the peel ply from the faying surface to provide a clean, high-area surface ideal
for bonding. Removal shall be accomplished in the ECA.
9. Quality Assurance of Composite Facings
9.1 Handling—Parts with the peel ply removed or being removed shall be handled using clean gloves or other methods to
prevent surface contamination.
9.2 Marking—All processed parts shall be marked with the date and time of manufacture. If the surface with the peel ply
removed must be marked, marking shall be lightly scribed.
9.3 Written Process Procedure—Each processor shall keep a written record of the date and time the peel ply was removed, the
time placed into the ECA, and the time the facing was bonded.
9.4 Visual Inspection—After removal of the peel ply, the faying surface shall be inspected for defects as defined by the
procurement document. Any defects shall be recorded.
10. Shelter Panel Construction
10.1 The matrix resin, fiber reinforcement, thickness of the facings, edge closure details, core type, and the weights and sizes
of the panels shall be as specified in the procurement document. Unless otherwise specified, the allowable deviation from flatness
of the bonded panel shall be within 1.5 mm ( ⁄16 in.) when measured as specified in 14.3.115.3.1 against the concave side of the
panel. With the panel in a horizontal position, lay the straight edge on the panel surface and measure the maximum gap between
the straightedge and the panel. The facing surfaces may contain local bulges or depression within the allowable flatness tolerance
specified above.
10.2 Edge Closures and Framing Members—The edge closures and framing members shall be as specified in the shelter design
specification. When the shelter design requires the edge closures and framing members to be b
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