This specification covers a rigid wall, two-side expandable shelter constructed of aluminum-faced, nonmetallic honeycomb sandwich panels and meeting the International Organization for Standardization (ISO) cargo container specification in the transport mode. Design and construction of the expandable shelter shall conform to the requirements specified. The shelter shall be free of panel delaminations and shall meet all physical and environmental requirements specified. Inspection requirements shall be classified as follows: first article inspection; comparison sample inspection; and quality conformance inspection. The following tests shall be performed to conform to the specified requirements: electrical continuity testing; water leakage and operational testing; performance testing; packaging examination; thermal shock test; panel interchange test; floor loads test-static load; roof load test; step test; airtightness test; low temperature test; high temperature test; humidity and temperature aging test; blackout test; panel watertightness test; insert working load test; rail transportability test; impact resistance test; drop test; towing test; water leakage test (shelter mode); water leakage test (container mode); water leakage test (shelter mode fully loaded); water leakage test (container mode fully loaded); fluorescent light temperature test; solar load test; operational test; lifting test; six-high stacking test; longitudinal restraint test; racking test; lashing test; end wall strength test; sidewall strength test; lifting from fork lift pockets test; heat transfer test; adhesion of paint test; panel delamination test; thickness test; electrical system test; and panel frame airtightness test.