Overview
ISO 7315:1988 specifies the envelope dimensions for aerospace “P” clamps (loop clamps) used in fluid systems. It defines the maximum and minimum dimensional limits for clamps installed using a bolt with a nominal diameter of 5 mm. The standard establishes a dimensional envelope (overall shape and key locations) but is explicitly not an interchangeability standard; detailed tolerances are to be given in the individual parts‑standard drawings.
Key topics and requirements
- Scope: Applies to “P” (loop) clamps intended for installation, support and guiding of rigid tubing or hose assemblies in aerospace equipment. Can also be used for cable looms.
- Bolt specification: Dimensions apply when clamps are installed with a bolt of nominal diameter 5 mm.
- Dimensional envelope: Table 2 defines the maximum/minimum envelope dimensions and the proper tube location relative to the mounting plane and fastening point. Dimensions apply with the tube assembled in the tightened clamp.
- Classification by temperature: Clamps are grouped into six types according to intended temperature range:
- Type 1: -55 to +70 °C
- Type 2: -55 to +135 °C
- Type 3: -55 to +200 °C
- Type 4: -55 to +320 °C
- Type 5: -55 to +400 °C
- Type 6: -55 to +650 °C
- Construction types: “P” clamps may be single‑component or multi‑component (metal support with plastomer/elastomer cushion or sheathing).
- Non‑preferred tube sizes: The standard table includes nominal diameters DN 4 up to DN 100; certain DN sizes are identified as non‑preferred (DN 14, 18, 22, 28, 36, 45, 56, 70, 90).
- Tolerances and parts drawings: Specific manufacturing tolerances and detailed geometry are defined in the parts standards/drawings for each clamp type and are not contained in ISO 7315.
Applications and users
ISO 7315 is practical for:
- Aerospace design engineers specifying tubing support and routing for hydraulic, fuel, pneumatic and environmental control systems.
- Component manufacturers and suppliers producing “P” clamps to aerospace dimensional envelopes.
- Maintenance, repair and overhaul (MRO) teams and installation technicians verifying clamp fit and tube location.
- Procurement and quality assurance professionals ensuring supplied clamps meet required envelope dimensions.
Keywords: ISO 7315, P clamps, loop clamps, aerospace, envelope dimensions, fluid systems, tubing clamps, clamp dimensions, temperature classification, DN sizes.
Related standards
- ISO 6771 - referenced for pressure and temperature classifications applicable to aerospace fluid systems.
- Individual parts‑standard drawings for each clamp type (define tolerances and manufacturing details).