| Push-to-Connect Fittings | Polyurethane, nylon, and polyethylene tubing; common metric sizes from 4 mm to 12 mm and inch sizes from 1/8 in to 1/2 in | Nickel-plated brass, stainless steel, engineering polymer, and elastomer seals | Tube is inserted directly into an internal collet and sealed by an O-ring | Approximately 0.8–1.0 MPa for many industrial pneumatic designs; confirm by size, material, and temperature | Approximately −20°C to +80°C for common elastomer-sealed designs | ISO 14743 for push-in connectors; manufacturer test specifications | Request leakage-test results, tube-retention data, seal material details, and dimensional drawings |
| Compression Tube Fittings | Rigid metallic or polymer tubes; commonly available for 4–16 mm metric tubing and comparable inch sizes | Brass, stainless steel, aluminum, ferrules, and sealing rings | Threaded nut compresses a ferrule around the tube | Often approximately 1.0–3.0 MPa, depending on tube wall thickness, material, and fitting size | Commonly approximately −40°C to +120°C; seal selection may reduce or extend this range | ISO 8434-1 for selected metallic compression-style connections; applicable national standards | Verify pressure-rating calculations, ferrule geometry, tube-wall requirements, and repeat-assembly performance |
| Threaded Adapter Fittings | Used with pneumatic tubing, valves, cylinders, manifolds, and air preparation equipment | Brass, stainless steel, plated steel, or reinforced polymer | Male or female pipe threads, often combined with a tube connection | Typically approximately 0.7–2.0 MPa for compressed-air systems, subject to thread size and construction | Commonly approximately −20°C to +100°C | ISO 7-1 for pressure-tight pipe threads; ISO 228-1 for parallel pipe threads where applicable | Confirm thread standard, gauge inspection records, thread tolerance, sealing method, and cross-border compatibility |
| Bulkhead Fittings | Polyurethane, nylon, polyethylene, or metallic tubing; commonly 4–12 mm metric sizes | Nickel-plated brass, stainless steel, polymer body, and elastomer seals | Tube connection passes through a panel or enclosure and is secured with a retaining nut | Usually approximately 0.6–1.0 MPa in general pneumatic applications | Approximately −20°C to +80°C for common industrial versions | ISO 14743 where the tube interface is a push-in connection; panel dimensions must be supplier-specific | Check panel-hole diameter, maximum panel thickness, torque requirements, vibration resistance, and leak testing |
| Elbow and Tee Fittings | Compatible with common pneumatic tubing sizes from 4 mm to 12 mm and selected inch sizes | Brass, stainless steel, acetal, polyamide, and sealing elastomers | Push-in, compression, or threaded configurations in 90-degree and branch layouts | Commonly approximately 0.6–1.0 MPa for compact push-in designs | Approximately −20°C to +80°C for standard seal materials | ISO 14743 for applicable push-in tube connections; internal flow testing recommended | Compare flow-rate data, minimum bend radius, insertion depth, orientation strength, and dimensional consistency |
| Bulkhead Union and Straight Union Fittings | Same-size or reducing connections for nylon, polyurethane, polyethylene, and related tubing | Nickel-plated brass, polymer, stainless steel, and elastomer seals | Joins two tubes directly or connects tubes across a panel | Typically approximately 0.8–1.0 MPa for general-purpose pneumatic products | Approximately −20°C to +80°C | ISO 14743 for suitable push-in configurations | Verify tube-size accuracy, pull-out force, leak rate, body-wall thickness, and availability of replacement seals |
| Stainless Steel Pneumatic Fittings | Metallic and polymer tubing; frequently selected for corrosive, washdown, or hygienic environments | Stainless steel grades such as 304 or 316, with compatible elastomer seals | Push-in, compression, or threaded connection | Often approximately 1.0–3.0 MPa, depending on connection type and tube specification | Approximately −40°C to +150°C with suitable seals and application conditions | Material certificates, corrosion-resistance testing, and applicable ISO or ASTM methods | Request grade certificates, surface-finish data, salt-spray or corrosion-test records, and seal compatibility information |
| Miniature Pneumatic Fittings | Small tubing commonly from 2 mm to 6 mm outside diameter | Nickel-plated brass, stainless steel, polymer, and miniature elastomer seals | Miniature push-in or threaded connection | Commonly approximately 0.5–0.8 MPa, depending on bore size and body design | Approximately −10°C to +60°C for many compact assemblies | Supplier dimensional standards, ISO-based test procedures, and application-specific validation | Review minimum operating flow, dead volume, insertion depth, precision machining, and low-pressure leakage results |
| Supplier Qualification Checklist | All requested tube sizes, thread systems, and regional specifications | Material traceability for metals, polymers, coatings, and seals | Documented production, inspection, packaging, and change-control procedures | Rating must be supported by product drawings, test reports, and clearly defined operating conditions | Temperature rating must identify the seal compound, medium, pressure, and exposure duration | ISO 9001 certification, applicable product standards, RoHS or REACH declarations where required | Verify legal company records, factory audit results, sample consistency, inspection plans, complaint handling, and shipment traceability |