ASTM E1975-22

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:E1975 −22
Standard Specification for
Shelter, Electrical, Equipment S-280/G
This standard is issued under the fixed designation E1975; 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 E631 Terminology of Building Constructions
E864 Practice for Surface Preparation of Aluminum Alloys
1.1 This specification covers one type of lightweight field
to Be Adhesively Bonded in Honeycomb Shelter Panels
and mobile shelter designed for transport by cargo truck, fixed
E1730 Specification for Rigid Foam for Use in Structural
orrotarywingedaircraft,byrail,andship,asShelter,Electrical
Sandwich Panel Cores
Equipment S-280/G (see 15.5).
E1749 Terminology Relating to Rigid Wall Relocatable
1.2 The values stated in inch-pound units are to be regarded
Shelters
as standard. The values given in parentheses are mathematical
E1773 Practice for Sealing RigidWallTactical Shelters with
conversions to SI units that are provided for information only
Polysulfide Based Sealants
and are not considered standard.
E1794 Specification for Adhesive for Bonding Foam Cored
1.3 The following safety hazards caveat refers only to the
Sandwich Panels (200 °F Elevated Humidity Service),
test methods described in this specification. This standard does Type II Panels
not purport to address all of the safety concerns, if any,
E1801 Practice forAdhesive Bonding ofAluminum Facings
associated with its use. It is the responsibility of the user of this in Foam and Beam Type Shelters
standard to establish appropriate safety, health, and environ-
E1851 Test Method for Electromagnetic Shielding Effec-
mental practices and determine the applicability of regulatory tiveness of Durable Rigid Wall Relocatable Structures
limitations prior to use.
E1925 Specification for Engineering and Design Criteria for
1.4 This international standard was developed in accor- Rigid Wall Relocatable Structures
dance with internationally recognized principles on standard-
2.2 AWS Standards:
ization established in the Decision on Principles for the
AWS D17.1/D17.1M Specification for Fusion Welding of
Development of International Standards, Guides and Recom-
Aerospace Applications
mendations issued by the World Trade Organization Technical
AWS D17.2/D17.2M Specification for Resistance Welding
Barriers to Trade (TBT) Committee.
for Aerospace Applications
2.3 Federal Air Regulation (FAR):
2. Referenced Documents
FAR 25.853 Compartment Interior
2.1 ASTM Standards:
2.4 Military Standards:
C273/C273M Test Method for Shear Properties of Sandwich
MIL-DTL-14072 Finishes for Ground Electronic Equip-
Core Materials
ment
D1621 Test Method for Compressive Properties of Rigid
MIL-DTL-53039 Coating, Aliphatic Polyurethane, Single
Cellular Plastics
Component, Chemical Agent Resistant
D1622/D1622M Test Method forApparent Density of Rigid
MIL-DTL-55507 Shelter, Electrical Equipment, (With or
Cellular Plastics
Without Equipment), Packaging of
D2842 Test Method for Water Absorption of Rigid Cellular
MIL-STD-202 Electronic and Electrical Component Parts
Plastics
MIL-STD-252 Wired Equipment, Classification of Visual
and Mechanical Defects for Equipment, Electronic,
This specification is under the jurisdiction of ASTM Committee E06 on
Wired, and Other Devices
Performance of Buildings and is the direct responsibility of Subcommittee E06.53
on Materials and Processes for Durable Rigidwall Relocatable Structures.
Current edition approved May 1, 2022. Published May 2022. Originally
approved in 1998. Last previous edition approved in 2021 as E1975–21. DOI: Available from American Welding Society (AWS), 8669 NW 36 St., #130,
10.1520/E1975-22. Miami, FL 33166-6672, http://www.aws.org.
2 4
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Available from Flight Standards Service, Federal Aviation Administration
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM (FAA), 800 Independence Ave., SW, Washington, DC 20591, http://www.faa.gov.
Standards volume information, refer to the standard’s Document Summary page on Available from DLA Document Services, Building 4/D, 700 Robbins Ave.,
the ASTM website. Philadelphia, PA 19111-5094, http://quicksearch.dla.mil.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1975−22
MIL-STD-810G Environmental Engineering Considerations may occur between any two bonded surfaces, examples in-
and Laboratory Tests clude: separations between thermal barriers and members,
MIL-STD-1916 DOD Preferred Methods for Acceptance of between thermal barriers and skins, between members and
Product core, or between skins and core. They may be the result of a
MIL-STD-13231 Marking of Electronic Items poor quality bond or they could occur due to misuse or severe
handling of the panels or the shelter after bonding. Test
2.5 Drawings:
requirements of this specification shall not be construed as
SC-D-36423 Hold Down Assembly
misuseorseverehandlingasthesetermsapplytothedefinition
SC-D-36424 Cable Assembly
of delaminations (see 5.4).
SC-C-200154 Keeper
SM-D-450462 Panel Assembly, Emergency Exit
3.1.2 examination—examination consists of simple, gener-
SM-C-450466 Air Filter
ally nondestructive determinations of compliance, without the
SM-C-555515 Shock Mount
use of special testing equipment.
SM-B-563756 Sealer
3.1.3 inspection—inspection is the examination or testing,
SC-D-595509 Cover, Emergency Exit
or both, of supplies to determine compliance with the appli-
SC-B-595564 Core Material-Urethane, Light
cable requirements. Sampling is an element of inspection.
SC-B-595565 Core Material-Urethane, Heavy
3.1.4 testing—testing consists of determinations of
SM-D-615264 Intake Louver Assembly
compliance, using technical means.
DL-SC-A-621051 Modification Kit, Radio Frequency
3.1.5 voids—for the purpose of this specification, a void is
Interference, MK-1079/G
SM-D-781242 Door Fixture (S-280) Construction Tightness defined as any unauthorized separation or space within a
shelter panel or section, that is, any separation or space that is
Test
SM-D-781243 DrainFixture(S-280)ConstructionTightness in conflict with the drawings or other contractual requirements.
Voids range from gaps as wide as the space created by a
Test
SM-D-781244 S-280 Construction Tightness Test missing piece of core material to as thin as a break in the
continuity of material. Voids may be located solely within one
DL-SM-B-947080 Shelter, Electrical Equipment S-280C/G
type of material, such as a core material separation; they may
SM-D-947080 Shelter, Electrical Equipment S-280C/G
exist between adjacent materials, such as unbonded core
SM-D-947081 Panel Assembly, Front
material; or they may be located between other parts within a
SM-D-947082 Panel Assembly, Rear
panel, such as where a piece of material is missing, damaged,
SM-D-947083 Panel Assembly, Roof
or undersized. Voids may have been created at the time of
SM-D-947084 Panel Assembly, Floor
construction, such as where a part was omitted; or may be
SM-D-947085 Panel Assembly, Side
created at a later time, such as a core separation or delaminated
SM-D-947141 Corner, Lifting Eye (Machining)
skin (see 5.4).
SM-D-947142 Corner, Towing Eye (Machining)
SM-D-947143 Casting, Lifting and Towing Eye
NOTE1—Allotherterminologyrelatedtothisspecificationisdefinedin
SM-D-947160 Door Jamb Assembly
Terminologies E631 and E1749.
SM-D-947166 Door Assembly
SM-B-947179 Bonding Procedure
4. Material Requirements
SM-B-947180 Cleaning Procedure
4.1 General—Materials used in the construction of this item
SM-D-947181 Flatness and Squareness Measurements
shall be in accordance with the following requirements:
SM-B-947184 Adhesive
4.2 Core Material—Core material density, compressive
SM-D-947186 Test Weight Installation
strength, shear strength, flammability, and water absorption
SM-C-947230 Shock Mount
properties shall be in accordance with Specification E1730 and
SM-D-947235 Mounting Bracket, Skid
Drawings SC-B-595564 and SC-B-595565, as applicable (see
SM-C-947237 Shock Mount
12.2.1, 10.1, Table 1, and Table 2).
SM-D-947238 Skid Assembly
17-1-3274 Shelter, Electrical Equipment, S-280C/G
4.3 Adhesive—The shear strength of the cured adhesive and
(Shielded)
its bond to aluminum shall be in accordance with requirements
of Specification E1794 and the Drawing SM-B-947184. This
3. Terminology
requirement shall apply to the low temperature, room
3.1 Definitions:
temperature, and high temperature conditions and after the
3.1.1 delaminations—for the purpose of this specification, a humidity exposure and salt spray exposure conditions required
delamination is defined as the condition that exists within a
bySM-B-947184(see12.2.2,12.2.3,10.2,10.2.2,Table1,and
shelter section or panel when two surfaces that once were
Table 2).
bonded together are no longer bonded together. Delaminations
4.4 Sealer—The shear strength of the cured sealer and its
bond to aluminum shall be in accordance with the following
(see 10.2, 10.2.2, Table 1, and Table 2):
Available from U.S. Army Natick Soldier Research, Development, and Engi-
4.4.1 Low Temperature—200 psi (1.4 MPa) when tested at
neering Center, ATTN: RDNS-SEE-T, 15 General Greene Avenue, Natick, MA
01760-5018, https://www.army.mil/info/organization/natick. –65 °F 6 5 °F (–54 °C 6 3 °C) (see 12.2.2 and Table 2).
E1975−22
TABLE 1 First Article Specimens TABLE 3 Sequence of First Article Inspection
Requirements Test Requirements Test
Inspection Quantity Inspection
Subsection Subsection Subsection Subsection
Core material: 4.2 10.1 Cleaning 5.2 10.4
Density 5 for every grade or type 4.2 10.1.1 Welding 5.3 10.5
Compressive strength 5 for every grade or type 4.2 10.1.2 Lamination 5.4 10.6
Shear strength 5 for every grade or type 4.2 10.1.3 Interchangeability 5.6 10.8
Flammability 5 for every grade or type 4.2 10.1.4 Riveting 5.7 10.9
Water absorption 3 for every grade or type 4.2 10.1.5 Construction tightness 8.2 10.10
of urethane Finish 5.8 10.11
Adhesive 50 coupons 4.3 10.2 Marking 5.9 10.12
Sealer 50 coupons 4.4 10.2 Dimensional 5.1 10.13
Shock mounts SM-C-555515: 3 per –3 4.5 10.3.1 Visual and mechanical 9.3 10.14
SM-C-947237: 3 each Shelter weight 5.10 10.15
SM-C-947230: 3 each Door latch torque 8.3 10.16
A
Impact panel 1 from wall, 1 from floor 5.4.1 10.7 Moisture resistance 6.2 10.17
Hold down assembly 1 complete 9.2 10.32 Temperature 6.3 10.18
Eye casting hardness 1 casting in accordance 7.5.2 10.24.2 Thermal differential 6.4 10.19
with SM-D-947143 Rail transport 7.2.1 10.21
Drops 7.3 10.22
B, C
Construction tightness 8.2 10.10.1
Towing, simulated 7.4 10.23
TABLE 2 In-Process Inspection
Eye pulls 7.5.1 10.24.1
Air transport, simulated 7.2.2 10.25
Requirements Sampling Test
Inspection
Static door load 7.6 10.26
Subsection Subsection Subsection
Roof access steps 7.7 10.27
Core material: 4.2 . 10.1
Light tightness 8.4 10.28
Density 4.2 12.2.1 10.1.1
Electromagnetic interference suppression 8.5 10.29
Compressive strength 4.2 12.2.1 10.1.2
Watertightness 8.6 10.30
Shear strength 4.2 12.2.1 10.1.3
Fording 8.7 10.31
Adhesive: 4.3 . 10.2
Door latch torque (second time) 8.3 10.16
Low temperature 4.3 12.2.2 10.2
Room temperature 4.3 12.2.3 10.2 A
First article specimen testing shall be completed no later than the end of this test
High temperature 4.3 12.2.2 10.2
(see 11.1.1).
B
Sealer: 4.4 . 10.2
For correlation data purposes only. CTT test results are not to be used as
Low temperature 4.4.1 12.2.2 10.2
accept/reject criteria for the drop test.
C
Room temperature 4.4.2 12.2.3 10.2
Door portion and gasket portion only.
High temperature 4.4.3 12.2.2 10.2
Shock mounts 4.5 12.2.4 10.3.2
Cleaning 5.2 12.2.5 10.4
Welding 5.3 12.2.6 10.5
Lamination 5.4 12.2.7 10.6
Interchangeability 5.6 12.2.8 10.8
5. Construction Requirements
Riveting 5.7 12.2.9 10.9
Eye casting hardness 7.5.2 12.2.10 10.24.2
5.1 General—Theelectromagneticprotectedsheltershallbe
Construction tightness, 8.2 12.2.11 10.10.1
shelter
constructed in accordance with Drawing 17–1–3274 and all
subsidiary drawings and parts lists pertaining thereto and as
specified herein.
4.4.2 Room Temperature—200 psi (1.4 MPa) when tested at
5.2 Cleaning—See 12.2.5, 10.4, Table 2, and Table 3.
80 °F 6 10 °F (27 °C 6 6 °C) (see 12.2.3 and Table 2).
5.2.1 Welding and Bonding—All aluminum parts to be
4.4.3 High Temperature—75 psi (75 kPa) when tested at
welded or bonded shall be cleaned in accordance with Practice
200°F+0°F – 5°F (93°C + 0°C –3°C) (see 12.2.2 and
E864 and Drawing SM-B-947180. The inspection and records
Table 2).
maintenance requirements of Practice E864 and SM-B-947180
4.4.4 Sealer Shear, Humidity Exposure—The sealer and its
shallbemet.Arcweldedassembliesshallbecleanedtoremove
bond to the aluminum shall withstand exposure to 95 %
anyscale,oxidationproducts,andexcessflux.Anyacidusedin
relative humidity 65 % at 160 °F 6 5 °F (71 °C 6 3 °C) for
cleaning shall be completely neutralized and removed.
fourteen days.After exposure the sealer shall have a minimum
5.2.2 Other—All aluminum parts to be sealed at a sub-
average shear strength of 75 psi (520 kPa) when tested at
160 °F 6 5 °F (71 °C 6 3 °C). assembly or at final assembly shall be cleaned in accordance
4.4.5 Sealer Shear, Salt Spray Exposure—The sealer and its with Practice E864 and SM-B-947180. Part drawings which
cite a specific finish in accordance with MIL-DTL-14072 shall
bondtothealuminumshallwithstandexposuretothesaltspray
test. Method 509.6 of MIL-STD-810G using a 20 % NaCl be cleaned as required therein.After assembly the shelter shall
be free from particles or scale, flux, excess adhesive, excess
solution at 95 °F 6 5 °F (35 °C 6 3 °C) for fourteen days.
After exposure the sealer shall have a minimum average shear sealer, and other foreign material. The shelter shall be cleaned
prior to application of finish.
strength of 200 psi (1.4 MPa) when tested at 180 °F 6 10 °F
(27 °C 6 6 °C).
5.3 Welding—Allweldsshallhavethoroughpenetrationand
4.5 Shock Mounts—Shelter skid shock mounts shall be in good fusion and shall be free from splatter, scabs, blisters,
accordance with Drawing SM-C-555515, SM-C-947237, and abnormal pock marks, cracks, voids, slag inclusions, and other
SM-C-947230 (see 12.2.4, 10.3, 10.3.1, 10.3.2, Table 1, and defects. Welders shall be certified in accordance with AWS
Table 3). D17.1/D17.1M.Inertgasshieldedarcweldingshallbeusedfor
E1975−22
TABLE 4 Group C Inspection
welding of aluminum in accordance with the drawings, except
whereresistanceweldingisspecified(see12.2.6,10.5,Table2, Requirements Sampling Test
Inspection
Subsection Subsection Subsection
and Table 3).
Drops 7.3 12.3.3.1 10.22
5.3.1 Arc Welding—Except where required on the shelter A, B
Construction tightness 8.2 . 10.10
C
Watertightness 8.6 . 10.30
drawings, welded joints shall not require grinding of the
C
Fording 8.7 . 10.31
finished weld and shall not be ground. Welding to repair
C
Door latch torque 8.3 . 10.16
castings shall not be permitted.
EMI suppression 8.5 12.3.3.2 10.29
D, E, F
Watertightness 8.6 . 10.30
5.3.2 Resistance Welding—Resistance welding shall be in
D, E
Fording 8.7 . 10.31
accordancewithClassBAWSD17.2/D17.2M.Qualificationof
D, E
Door latch torque 8.3 . 10.16
welding machines and certification of welding schedules in
Hold down assembly 9.2 12.3.3.3 10.32
Corematerial: . . .
accordance with AWS D17.2/D17.2M is required prior to first
Flammability 4.2 12.3.3.4 10.1.4
article and production welding. Failure of any production
Water absorption 4.2 12.3.3.4 10.1.5
specimen or any production part to meet the requirements of
Adhesive . . . . . . . . .
Humidity exposure 4.3 12.3.3.4 10.2
AWS D17.2/D17.2M shall be cause for rejection of the
Salt spray exposure 4.3 12.3.3.4 10.2
production quantity represented by that specimen or part.
Sealer . . . . . . . . .
Humidity exposure 4.4.4 12.3.3.4 10.2
5.4 Lamination—The roof, floor, door, and each wall of the
Salt spray exposure 4.4.5 12.3.3.4 10.2
shelter shall be bonded without voids or delaminations (see
Shock mounts, complete 4.5 12.3.3.4 10.3.1
Impact panel 5.4.1 12.3.3.4 10.7
3.1.1 and 3.1.5) to the inner and outer skins and other adjacent
A
Environmentals: . 12.3.3.4 .
surfaces. No voids shall exist between the inner and outer
E
Moisture resistance 6.2 . 10.17
E
surfaces of the panels due to foam breaks, misfits, or lack of
Temperature 6.3 . 10.18
E
Thermal differential 6.4 . 10.19
adhesive. Bonding shall be in accordance with Practice E1801
G, H
EMI suppression 8.5 . 10.29
and SM-B-947179 (see 12.2.7, 10.6, Table 2, and Table 3).
E, G
Watertightness 8.6 . 10.30
E, G
5.4.1 Impact Resistance—The floor, door, and each wall of
Fording 8.7 . 10.31
E, G
Door latch torque 8.3 . 10.16
thesheltershallbecapableofwithstandingimpactbyaforeign
E
Rail transport 7.2.1 . 10.21
object. To determine compliance with this requirement, speci-
E, I
Drops 7.3 . 10.22
D, E, J
mens shall be fabricated and tested in accordance with 10.7.
Construction tightness 8.2 . 10.10
E, J
EMI suppression 8.5 . 10.29
Each specimen shall not suffer rupture or fracture of either of
E
Watertightness 8.6 . 10.30
the skins and shall not result in denting of the lower skin (see
E
Fording 8.7 . 10.31
E
Table 1 and Table 4). Door latch torque 8.3 . 10.16
Towing, simulated 7.4 12.3.3.4 10.23
5.5 Vapor Seal—Except for the breather holes required for
Air transport, simulated 7.2.2 12.3.3.4 10.25
the construction tightness test, and in accordance with the
A
These inspections shall be performed on the same (serial number) shelter.
B
shelter drawings, the inner and outer skins and all joints shall Door portion and gasket portion only.
C
If the EMI suppression test is to follow the drop test on the same shelter, these
be sealed to provide a vapor barrier against the entrance of
tests shall be done after EMI.
moisture to the core material and to the interior of the shelter D
To be performed only if EMI test followed drop test on the same shelter or if
(see 5.11, 10.30, and 10.31). (See Practice E1773). adjustment to gasket compression was necessary to satisfy EMI suppression
requirements.
E
5.6 Interchangeability—Like units, subassemblies,
Modification Kit MK-1079/G to remain installed during these tests.
F
If shelter was not drop tested prior to EMI testing, this watertightness test shall
assemblies, and replaceable parts shall be physically and
use only the nine nozzles located at the door end of the shelter.
functionally interchangeable without modification of the items G
If the transport test is to follow the environmental tests on the same shelter these
or the shelter. Individual items shall not be hand-picked for fit tests shall be done after the drop test.
H
This inspection may also satisfy sampling for EMI suppression in accordance
orperformance.Relianceshallnotbeplacedonanydimension,
with 12.3.3.2.
I
rating, characteristic, etc. not specified on the drawings. To
This inspection may also satisfy sampling for drop test in accordance with
determine compliance with this requirement, the items listed in 12.3.3.1.
J
For correlation data purposes only. CTT test results are not to be used as
10.8 shall be measured and shall be in accordance with the
accept/reject criteria for the drop test.
dimensions and tolerances specified on the applicable drawing
(see 12.2.8, Table 2, and Table 3).
5.7 Riveting—Nomorethanonerivetorrivnutintenandno
5.7.3 Mating Surface and Materials—The mating surface
morethantwoadjacentrivetsorrivnutsshallexhibitanyofthe
shall not be marred or indented due to rivet or rivnut
defectsspecifiedbelow(see12.2.9,10.9,Table2,andTable3).
installation, nor shall there be any distortion or warpage of the
5.7.1 Looseness—There shall be no evidence of looseness
mating materials. There shall be no foreign material between
parallel to the plane of the mating surfaces due to oversized
riveted surfaces. The term foreign material does not include
holes or looseness perpendicular to the plane of the mating
material required by and allied in accordance wit the shelter
surfaces due to rivets or rivnuts not being tightly sealed.
drawings.
5.7.2 Heads—Rivet and rivnut heads shall not be cut,
marred, chipped, eccentric, distorted, or otherwise mutilated. 5.8 Finish—The shelter shall be finished in accordance with
Countersunkrivetsandrivnutsshallnotprojectaboveorbelow the drawings and the paint finishes requirements of MIL-DTL-
the mating surface more than 15 % of the mating material 14072 (see 10.11, 10.14, and Table 3). The Government shall
thickness (see 10.9). have the option of painting the S-280C Shelters the following
E1975−22
colors using Chemical Agent Resistant Coating (CARC) in 5.11.6 Unless otherwise specified, all shelter dimensions
accordance with MIL-DTL-53039: shall remain in accordance with the drawings.
Option 1: CARC TAN 686 A (33446), 5.11.7 Any deformation of any mounting arrangement shall
Option 2: CARC GREEN 383 (34094), bewithindrawingtolerancesandshallnotcausedegradationof
Option 3: Three Color Camouflage per Drawing its retaining ability or of specified shelter performance.
13228E1360: CARC GREEN 383 (34094), CARC BROWN 5.11.8 The door and the emergency exit cover shall open
383 (30051), and CARC BLACK (37030). and close to their full extent without binding in the hinge(s) or
interfering against any portion of the door or cover jamb or
5.9 Marking—Marking shall be in accordance with the
gasket bearing areas.
drawings and MIL-STD-13231. Classification of defects in
5.11.9 There shall be no malfunction of the door latch
MIL-STD-13231isapplicable.Serialnumbersshallbemarked
mechanism.
in accordance with the drawings on the shelter and on the
5.11.10 There shall be no binding in the door brace pivot
nameplate in the space provided (see 10.12, 10.14, and Table
points or interference between brace components.
3).
5.11.11 When a tiedown is required, it shall not be damaged
5.9.1 Facsimiles—When specified (see 15.1.4), the contrac-
as a result of the test.
tor shall provide facsimiles of the nameplate and all data and
instruction plates required by DL-SM-B-947080 (see 15.1.3). 5.12 Construction Tightness Preconditioning—Prior to sub-
Each facsimile shall be in accordance with its drawing and mission for the specified qualification inspection, each shelter
shall include any and all information required to be inserted, shall show no evidence of air leakage through sealed seams,
except shelter serial number. Artwork shall be of a quality at joints,rivets,mountingbolts,etc.,whentestedandcorrectedin
least comparable to the drawing (see 10.14). accordance with 10.10.1.
5.10 Shelter Weight—The gross weight of the shelter, ex-
6. Environmental Requirements
cluding the hold down assembly, SC-D-36423, shall be as
6.1 General—The shelter shall meet the following environ-
follows (see 10.15, Table 3, and Table 5):
mental service conditions. Where a test is referenced, meeting
5.10.1 1400 lb 630lb(636 kg 614kg)withoutMK-1079(
thetestshallbeconsideredascompliancewiththerequirement
)/G installed, and
(see 5.11).
5.10.2 1410 lb 6 30 lb (640 kg 6 14 kg) with MK-1079(
)/G installed.
6.2 Moisture Resistance—Daily exposure up to 97 % rela-
tive humidity for 20 h and exposure at 100 % relative humidity
5.11 Service Integrity—Unless otherwise specified, all in-
with condensation for 4 h (see 10.17 and Table 3).
spections required herein shall not result in any of the defects
listed below. This service integrity requirement shall apply to
6.3 Temperature—The shelter shall withstand rapid tem-
the shelter both with and without Modification Kit, RFI,
perature changes and exposure to the following (see 10.18 and
MK-1079( )/G installed, as required by the individual inspec-
Table 3):
tions specified herein, (see 6.1, 7.1, 8.1, 10.0, 10.17, 10.18,
6.3.1 Operating—Ambient temperature in the range of
10.19.1, 10.21, 10.22.2, 10.23, 10.24.1, 10.25, 10.26, and
–65 °F to 6 125 °F (–54 °C to 52 °C) plus a solar load such
10.27).
that the outside skin reaches a minimum temperature of 200 °F
5.11.1 Thereshallbenodelamination,buckling,splitting,or
(93 °C). Exposure at the high extreme is not to exceed 4 h and
other deformation or structural weakening of the shelter.
at the low temperature extreme is not to exceed 72 h at any one
5.11.2 The vapor seal of 5.5 shall remain intact at all
time.
cross-sectional openings of the shelter and at all fillets and
6.3.2 Nonoperating—Exposure in the range of –80 °F to
fasteners.
+160 °F (–62 °C to +71 °C). Exposure at the high temperature
5.11.3 Brackets, lugs, flanges, inserts, bolts and any other
extreme is not to exceed 4 h and at the low temperature
mountingarrangementshallsecurelyretaintestloads,thedoor,
extreme is not to exceed 24 h at any one time.
and all hardware.
6.4 Thermal Differential—See 10.19 and Table 3.
5.11.4 There shall be no corrosion of any parts.
6.4.1 Thermal Deformation—The shelter shall withstand
5.11.5 There shall be no growth of the core material.
exposure to a temperature differential of 100 °F between the
inside and outside of the shelter (see 10.19.1).
TABLE 5 Group A Inspection
6.4.2 Heat Transfer—When specified (see 15.1.5), the over-
Requirements Test AQL %
all coefficient of heat transfer of the shelter shall not exceed
Inspection
Subsection Subsection Major Minor
0.28BritishThermalUnits(BTUs)perhourpersquarefootper
Construction tightness 8.2 10.10 . .
degree Fahrenheit (1.6 Watts per square metre per degree
Shelter portion (audit only) 8.2 10.10.1 1.00 . . .
Door portion 8.2 10.10.2 1.00 . . .
Kelvin). This overall coefficient shall apply to the shelter with
Gasket portion 8.2 10.10.3 1.00 . . .
the door and the emergency exit cover closed and with no
Visual and mechanical 9.3 10.14 1.00 4.00
additional thermal sealing (see 10.19.2).
Dimensional 5.1 10.13 1.00 . . .
A
Door latch torque 8.3 10.16 1.00 . . .
Shelter weight 5.10 10.15 1.00 . . .
7. Structural Integrity Requirements
A
Door latch torque to be repeated during the final cursory visual mechanical
7.1 General—The shelter shall be capable of complying
inspection.
with the following requirements. Unless otherwise specified
E1975−22
when a payload is required, the shelter shall be loaded with in accordance with 10.24.1 with no damage to the eye
7100 lb (3227 kg). The contractor shall fashion an appropriate assemblies, or shelter (see Table 3 and Table 6).
simulated payload design to be used for all testing. This 7.5.2 Eye Casting Hardness—Each lifting and towing eye
payload design shall be a modification of drawing SM-D- casting in accordance with SM-D-947143 shall be properly
947186 and shall be approved by the procuring agency prior to aged and hardened to a hardness of 75 Brinell Standard Type
its use in any test. Where a test is referenced, meeting the test (10 mm ball, 500 kg load) prior to machining (see 12.2.10,
shall be considered as compliance with the requirement (see 10.24.2, Table 1, and Table 2).
5.11, 10.21, 10.22, and 10.23).
7.6 Static Door Load—The door, door frame, and door
7.2 Transportability—The shelter, with payload, shall be hardware shall be capable of supporting a vertical load of
capable of being picked up by a crane using the hold down 200 lb(90kg)appliedinaccordancewith10.26.Thereshallbe
assembly, SC-D-36423, transported while suspended from the no damage and the door shall seal properly, as determined by
crane, and lowered to any predetermined point on the ground. inspecting in accordance with 10.10.3 (see Table 3 and Table
The shelter shall also be capable of being transported as 6).
follows:
7.7 Roof Access Steps—Each roof access step installed on
7.2.1 Rail Transport—The shelter, with payload, shall be
the shelter shall be capable of supporting a vertical load of
capableofbeingloadedandbracedonaflatcarforshipmentby
400 lb (180 kg) applied in accordance with 10.27. There shall
rail (see 10.21, Table 3, and Table 4).
benodamageandthestepshallopenandclosewithoutbinding
7.2.2 Air Transport—The shelter shall have adequate
(see Table 3 and Table 6).
strength to secure 7100 lb (3227 kg) of equipment mounted in
the shelter when exposed to 3.0 G’s acceleration with the
8. Tightness Requirements
shelter suspended by its lifting eyes (see 10.25, Table 3, and
8.1 General—The shelter shall be capable of meeting the
Table 4).
followingtightnessrequirements.Exceptfor8.5,theserequire-
7.3 Drops, Flat and Rotational—The shelter, with a 7100 lb ments apply both with and without MK-1079/G installed (see
(3227 kg) payload, shall be capable of withstanding drops of
5.11).
18 in. (460 mm) onto concrete during handling.After all drops
8.2 Construction Tightness—The shelter shall be airtight to
of 10.22, the inside dimensions of the shelter shall remain in
the extent that it shall be capable of achieving and maintaining
accordance with Drawing SM-D-947080. There shall be no
a pressurized state without leakage when tested in accordance
permanent deformation, buckling, delamination (see 3.1.5),
with10.10(see12.2.11,Table2,Table3,Table4,andTable5).
sealer separation, or structural weakness to any part of the
8.3 Door Latch Torque—When tested in accordance with
shelter, except that deformation in the skids and skid mounting
1 10.16, the door latch torque shall not exceed the following (see
brackets shall not exceed ⁄4 in. (6 mm), and a quarter moon
Table 3, Table 4, and Table 6):
shaped (3 in. by 13 in. (75 mm by 330 mm)) delamination
8.3.1 15 ft-lbf maximum when MK-1079/G is not installed,
(bulge) that appears on the interior front panel along the floor
and
between the two center members shall not be considered cause
8.3.2 30 ft-lbf maximum when MK-1079/G is installed.
for failure. The door and cover shall open and close to the full
extent specified on the applicable drawing on DL-SM-D-
8.4 Light Tightness—No direct rays of light shall be visible
947080 without binding in the hinge(s) or interfering against
through the intake louver assembly when tested in accordance
any portion of the jamb or bearing areas, or both, (see 12.3.3.1,
with 10.28 and viewed by an observer from the darkened
10.22.1, 10.22.2, Table 4, and Table 6).
shelter interior (see Table 3 and Table 6).
7.4 Towing, Simulated—The shelter shall be capable of
8.5 Electromagnetic Interference (EMI) Suppression)—The
withstanding a 4200 lb shear force applied to the plane of the
shelter shall be capable of being shielded from electromagnetic
skid attachment without damage to any part of the shelter, skid
interference by the installation of Modification Kit, Radio
assemblies or skid mounting brackets (see 10.23, Table 3, and
Frequency Interference, MK-1079/G in accordance with DL-
Table 4).
SC-A-621051 and with no other modification. Shielding shall
provide a minimum attenuation of radiated and induced EMI
7.5 Lifting and Towing Eyes—See 10.24.
fields as specified in Specification E1925 within the frequency
7.5.1 Eye Pulls—Each lifting and towing eye assembly,
range of 100 kHz to 10 Ghz when tested in accordance with
installed on the shelter, shall be capable of withstanding loads
10.29. Should a shelter subjected to the EMI test fail to pass,
another shelter from the same lot shall be subjected to the EMI
TABLE 6 Group B Inspection
test (see 12.3.3.2, 10.29, Table 3, and Table 4).
Requirements Test
Inspection AQL %
8.6 Water Tightness—The shelter shall be watertight when
Subsection Subsection
Finish 5.8 10.11 6.5
tested and inspected in accordance with 10.30. This require-
Eye pulls 7.5.1 10.24.1 6.5
ment shall be met without the use of any external or internal
Static door load 7.6 10.26 6.5
Roof access steps 7.7 10.27 6.5 sealing, caulking, taping, etc., not specified on the drawings
A
Construction tightness 8.2 10.10 1.0
(see Table 3 and Table 4).
Light tightness 8.4 10.28 6.5
A 8.7 Fording—The shelter shall be capable of being im-
Door portion and gasket portion only.
mersed in water to a depth of 21 in. (530 mm) measured from
E1975−22
the bottom of the shelter skids. There shall be no leakage or weighing jig shall also be weighed at this time; for the final
damage to the structure or finish when tested and inspected in weight, weigh the specimens and remove from the water in
accordance with 10.31. This requirement shall be met without reverse order; calculate the water absorption as follows:
theuseofanyexternalorinternalsealing,caulking,taping,etc. 2
lb water⁄ft 5 W 2 W 2
~~~ !
2a 1a
not specified on the drawings and without the use of a special
2 2
W 2 W ⁄A 3 2.048 lb ⁄ ft ⁄ g ⁄ cm (1)
~ !! ! ~ !
2 3
fording kit (see Table 3 and Table 4).
where:
9. Other Requirements
W = initial submerged weight of jig and samples (g),
1a
9.1 First Article—When specified (see 15.1.2), the contrac- W = initial submerged weight of jig (g),
2a
tor shall furnish sample items for first article inspection and W = final submerged weight of jig (g),
W = final submerged weight of jig and samples (g), and
approval (see 11.1).
A = specimen surface area (cm ).
9.2 Hold Down Assembly—A combination lift and tiedown
10.2 Coupon Specimens—Coupon specimens for both adhe-
device shall be provided as part of each shelter. This device
sive and sealer tests shall be lap joints fabricated in accordance
will be used for lifting the shelter and for tying down the
with SM-B-947184. Five coupons are required for each of the
shelter in military trucks. The device shall be in accordance
five test conditions. For first article inspection, ten coupons are
with Drawing SC-D-36423, Hold DownAssembly. Each cable
required for each of the five test conditions (see 4.3, 4.4,
assembly in accordance with Drawing SC-D-36424 shall be
12.2.2, 12.2.3, Table 1, Table 2, and Table 4).
capable of withstanding a tensile load of 14 000 lb (6350 kg)
10.2.1 Compatibility of Fabrication and Cure—Verify two
as specified on SC-D-36424 (see 12.3.3.3, 10.25, 10.32, Table
or more part mixes of adhesive as being in accordance with
1, and Table 4).
SM-B-947184 before coupons are fabricated. Verify two or
9.3 Workmanship—The shelter shall be manufactured with
more part mixes of sealer as being in accordance with
the degree of workmanship normally considered appropriate
SM-B-947184 before coupons are fabricated. Calibrate auto-
for each of the areas listed under Section 5 (see 10.14, Table 3,
matic dispensing machines, when used to mix and deliver two
and Table 5).
or more part adhesive or sealer, at least once every 4 h.
Fabricate coupon specimens and cure using materials,
10. Tests Required
processes, and conditioners compatible with those used on
10.1 Core Material—Subject core material specimens to the
panels and shelters, including:
followingtests.Foreachtestasetoffivespecimensisrequired
10.2.1.1 Same batch and type of material,
for each type or grade of core material used in the shelter.
10.2.1.2 Surface conditions of and method of preparing
Fabricate specimens from actual shelter core material pieces
materials to be bonded or sealed,
randomly selected from production core material parts. Speci-
10.2.1.3 Time elapsed between application of adhesive to
mendimensionsshallbewithin 60.015in.(60.4mm).Except
the first panel in a lot of panels and application of temperature
for flammability, the requirements of 4.2 shall be met by the
and pressure to the lot of panels,
average of the specimen results, with the lowest result no less
10.2.1.4 Time, temperature, and pressure of cure. Cure
than 90 % of the required value (see 12.2.1, Table 1, and Table
sealercouponsatapressureof5 psi 6 ⁄2psi(34 kPa 63kPa),
2).
and
10.1.1 Density—Testfivespecimens,each2 in.by3 in.by3
10.2.1.5 Minimum cure time before handling.
in. (50 mm by 75 mm by 75 mm), in accordance with Test
10.2.2 Shear Tests—Test coupons at the specified tempera-
Method D1622/D1622M (see Table 1 and Table 2).
ture after being subjected to the specified exposure, if appli-
10.1.2 Compressive Strength—Test five specimens, each
cable. Stabilize the temperature of the coupons at the specified
2 in. by 3 in. by 3 in. (50 mm by 75 mm by 75 mm), in
level and measure by a thermocouple attached to the coupon
accordance withTest Method D1621, ProcedureA(see Table 1
over the lap joint. The thermocouple shall not be attached on
and Table 2).
that side of the lap joint closest to the heat or cold source nor
10.1.3 Shear Strength—Test five specimens, each ⁄2 in. by
shall the method of attachment impair the application or
1 ⁄2 in. by 6 in. (13 mm by 38 mm by 150 mm), in accordance
measurement of the shear force in any way. Apply the shear
with Test Method C273/C273M, except apply the load at a
force to destruction. Set rate of application of force under
constant rate such that the maximum load will occur in 1 min
no-load conditions and be constant at 1 in./min 6 2s
or more (see Table 1 and Table 2).
(25 mm⁄min 6 2 s). Meet the requirements of 4.3 for adhesive
10.1.4 Flammability—Determine flame resistance of the
and 4.4, with subparagraphs, for sealer by the average of the
1 1
five specimens, each ⁄2 in. by 1 ⁄2 in. by 7 in. (13 mm by
coupon results, with the lowest result no less than 90 % of the
38 mm by 178 mm), (see Table 1) in accordance with FAR
required value for adhesive and 70 % of the required value for
25.853, Appendix F. The average extinguish time shall not
sealer. Failure to meet these requirements shall be cause for
exceed 15 s, and the average burn distance shall not exceed 6
rejection of all panels and shelters fabricated using that
in. (150 mm).
production quantity of adhesive or sealer represented by that
10.1.5 Water Absorption—Test three specimens, each 6 in.
failed coupon or average.
by 6 in. by 3 in. (150 mm by 150 mm by 75 mm), in
accordance with Test Method D2842 with the following 10.3 Shock Mounts—Determine compliance with 4.5 by the
changes: weigh each specimen as it is first submerged; the following inspections:
E1975−22
10.3.1 Complete Inspection—Inspect the shock mount ma- has been located, interrogate said area in detail by at least one
terial by subjecting it to all tests specified on Drawing hammer impact per inch in all directions. Mark the delamina-
SM-C-555515, SM-C-947237, or SM-C-947230. Fabricate
tion boundaries as the point of acoustic change (“deadening”)
where possible, test specimens from actual shock mounts plus ⁄2 in. (6 mm). The requirements of 5.4 shall be met (see
furnished for the shelter. Subject three shock mounts in
12.2.7, Table 2, and Table 3).
accordance with each shock mount drawing to the depression-
10.7 Impact Resistance—Fabricate an impact resistance
deflection test of its respective drawing. The requirements of
specimen in accordance with Fig. 2. The specimen shall
4.5 shall be met (see Table 1).
containonlyonecontinuouspieceofcorematerialbondedwith
10.3.2 Abbreviated Inspection—Inspect the shock mounts
adhesive, without voids or delaminations, to two aluminum
by subjecting them to the hardness, resilience, and depression-
skins. For testing, support the specimen along its four edges by
deflection tests in accordance with SM-C-555515, SM-C-
aframeworkbackedbyconcrete.Theframeworkshallbemade
947237, and SM-C-947230. The requirements of 4.5 shall be
of four pieces of 2 in. by 4 in. (50 mm by 100 mm) (nominal)
met (see 12.2.4 and Table 2).
lumber. Rigidly bolt the frame together to form a square 24 in.
10.4 Cleaning—Inspection of the cleaning process shall be
(610 mm) on a side (outside dimension) and 4 in. (100 mm)
in accordance with Practice E864 and SM-B-947180. Any
high. Rest the frame on the 2 in. (50 mm) face. Bolt the
noncompliance shall require recleaning of the parts processed
specimen to the frame with two ⁄4 in. (6 mm) diameter bolts
since the last acceptable inspection. The requirements of 5.2,
per edge. Leave a gap of 0.010 in. (0.3 mm) under each bolt.
with subsections, shall be met (see 12.2.5, Table 2, and Table
Then impact the specimen with a 70 lb (32 kg) steel cylinder
3).
3 in. (75 mm) in diameter and hemispherical at one end.
10.5 Welding—Visually inspect arc welding in accordance
Vertically drop the cylinder 30 in. (762 mm) so that the
with the requirements of maintenance sampling for production
hemispherical end of the cylinder strikes the center of one skin
of AWS D17.1/D17.1M. For resistance welding, fabrication
of the specimen on a horizontal plane. After impact, the
and inspection of production specimens and inspection of
specimen shall meet the requirements of 5.4.1. Then cut open
production parts shall be in accordance with AWS D17.2/
the specimen and examine for conformance with Fig. 2 and the
D17.2M. The requirements of 5.3, with subsections, shall be
requirements specified herein (see Table 1).
met (see 12.2.6, Table 2, and Table 3).
10.8 Interchangeability—To determine compliance with the
10.6 Lamination—Inspectpanelsandsheltersforlamination
interchangeability requirement of 5.6, measure the following
using a tap hammer in accordance with Fig. 1. Accomplish
dimensions and characteristics and check in process (see
inspection by tapping the panel skins with the spherical end of
12.2.8, Table 2, and Table 3):
the hammer. Use the flat end of the hammer for tapping into
10.8.1 Overall dimensions, squareness, parallelism, flush-
corners. Tapping force shall be approximately equal to that
nessofthecornermiterjoints,andflatnessatthegasketseating
produced when the head is raised approximately 1 in. (25 mm)
and contact surfaces of the items listed below. Inspect flatness
above the panel and allowed to fall against the panel and with
by measuring the flatness of the four sides and the flatness at
the center of arc 12 in. (300 mm) from he head. A hammer
the corners along the diagonals using a straight edge with a
blow on a laminated area produces a “solid” or “firm” or
center rest point.
“ringing” sound whereas a delaminated area produces a “dead-
10.8.1.1 Door in accordance with SM-D-947166,
ened” or “hollow” or “metallic slap” sound. The extent of
10.8.1.2 Emergency exit opening in the door in accordance
interrogation of each side of each panel shall be at least four
with SM-D-947166,
hammer impacts per square foot of panel area between
membersandatleastfourhammerimpactspersquarefootover 10.8.1.3 Emergency exit panel in accordance with SM-D-
members on the interior side of the panel. Once a suspect area 450462, and
NOTE 1—Material—Aluminum 6061–T6 or equivalent.
NOTE 2—Tolerance—6 ⁄32 in. (1 mm).
FIG. 1Tap Hammer
E1975−22
FIG. 2Impact Resistance Specimen
10.8.1.4 Emergency exit cover in accordance with SM-C- portions indoors and in still air. Correct any leaks found during
595509. any portion of this test before proceeding with the next portion
10.8.2 Overall dimensions, squareness, parallelism, and lo- of this test (see 8.2, Table 2, Table 3, Table 4, Table 5, and
cation of mounting holes of the louver assembly in accordance
Table 5).
with SM-D-615264.
10.10.1 Shelter Portion—Place the shelter in a position that
10.8.3 Dimensions of air filter in accordance with SM-C-
allows access to all exterior joints and fasteners on all surfaces
450466.
and test as follows (see 12.2.11, Table 2, and Table 5).
10.8.4 Locations of center marks for mounting members in
10.10.1.1 Assembled Condition—Use no sealant, caulking,
accordance with SM-D-947083, SM-D-947084, SM-D-
tape, etc., on the shelter except as detailed on the drawings.
947085, SM-D-947081, and SM-D-947082.
Complete the shelter except the skid mounting bracket (SM-
10.8.5 Mounting dimensions of hinges in accordance with
D-947235) and related shims and the latch keepers (SC-C-
SM-D-947080 and of latches in accordance with SM-D-
200154) and related shims shall not be installed. The door
947166.
assembly (SM-D-947166) need not be installed. Install the
10.8.6 Overall dimensions of skids and location of mount-
rivnutsusedtoconnecttheseparts,however,intheshelter.The
ing holes in accordance with SM-D-947238, SM-D-947080,
shelter exterior need not be painted before the test. For Group
and SM-D-947235.
AAudit testing,
...