RFQ Today
Certifications: material data sheets, FDA 21 CFR compliance (food-grade grades), RoHS / REACH compliance, hydrostatic pressure test records, and complete export documentation packages for construction and industrial project supply.
Nylon
& PTFE
Tubing
A world-class technical reference for EPC contractors, instrument and process engineers, procurement heads, and global project buyers specifying Nylon PA12, PA11, and PTFE tubing for compressed air, instrument air, pneumatic control, chemical lines, hydraulic pilot circuits, fuel lines, food and pharmaceutical transfer, vacuum systems, and any application requiring a lightweight, flexible, chemically resistant, and pressure-rated polymer tubing solution.
Engineering Properties
& Selection Principles
Nylon (polyamide) and PTFE tubing are the two dominant polymer tubing materials for industrial fluid and gas transmission — each with a distinct combination of pressure rating, chemical resistance, temperature range, flexibility, and regulatory compliance that governs their selection for specific applications.
1.1 — Technical Overview and Engineering Context
Nylon (polyamide, PA) tubing is the most widely used polymer tubing for industrial compressed air, pneumatic control, and instrument air systems — providing an optimal balance of burst pressure resistance (PA12 rated to 15–16 bar at ambient temperature for 10 mm OD × 1.5 mm wall), flexibility (easily routed around equipment), and dimensional precision (OD tolerance ±0.1 mm enabling reliable collet engagement in push-in fittings). PA12 (polyamide 12) is the dominant grade — lower moisture absorption than PA6 or PA11 gives PA12 superior dimensional stability in wet and humid environments, maintaining the tight OD tolerance critical for push-in fitting collet grip even after prolonged water exposure.
PTFE (polytetrafluoroethylene) tubing occupies a completely different performance envelope — chemical inertness to virtually all process fluids, continuous service temperature to 260°C, zero moisture absorption, and the lowest coefficient of friction of any solid polymer (μ ≈ 0.04). PTFE tubing is specified wherever Nylon tubing would fail: high-temperature process fluid lines, aggressive chemical transfer lines, pharmaceutical and food-contact fluid lines requiring zero extractable compounds, electrical cable conduit in chemical plant, and hydraulic pilot lines where the fluid is an aggressive ester or phosphate ester hydraulic fluid that degrades nylon rapidly. The trade-off: PTFE is more expensive than PA12, less flexible at small bend radii, and has lower burst pressure at equivalent wall thickness due to PTFE’s lower tensile strength compared to nylon.
1.2 — Nylon Tubing Grade Classification
PA12 (Polyamide 12) — Standard Industrial Grade
The most common industrial pneumatic and instrument air tubing grade. PA12 is produced by ring-opening polymerisation of laurolactam — the 12-carbon monomer chain gives PA12 the lowest moisture absorption of the common polyamide grades (≤ 0.25% at 23°C, 50% RH vs 2.8% for PA6). Lower moisture absorption means: better dimensional stability of the OD in wet installations (maintaining push-in fitting collet grip); better electrical resistivity stability in humid environments; and lower susceptibility to hydrolysis in steam and hot water service. Working pressure rating (10 mm OD × 1.5 mm wall): 16 bar at 20°C; 12 bar at 60°C. Temperature range: −40°C to +80°C continuous; short-term to +100°C. Per ISO 14743 and DIN 74324.
PA11 (Polyamide 11) — High-Performance Bio-Based
PA11 (polycondensation of 11-aminoundecanoic acid from castor oil) provides superior flexibility to PA12 at low temperature, better UV resistance, and bio-based raw material origin. PA11 has: lower density (1.03 g/cm³ vs 1.01 for PA12 — marginal); superior flexibility at −40°C; better resistance to zinc chloride and calcium chloride de-icing agents (important for automotive and outdoor pneumatic applications). Used for: automotive brake lines (SAE J844); aerospace pneumatic ducting (MIL-T-8504); outdoor pneumatic systems in sub-zero environments; and applications requiring bio-based polymer certification (sustainability specifications). Higher cost than PA12 — specify PA11 only where the specific performance advantage is required.
PA6 (Polyamide 6) — Lower Cost, Higher Moisture Absorption
PA6 (polycaprolactam) — lower raw material cost than PA12 but significantly higher moisture absorption (2.5–3.0% at 23°C, 50% RH). High moisture absorption causes dimensional swelling of the PA6 tube OD — swollen OD can prevent push-in fitting collet engagement, and the expanded OD creates excessive grip in the collet that makes tube removal difficult or impossible without damaging the collet teeth. PA6 is acceptable for dry indoor applications in moderate temperature environments; it is NOT suitable for instrument air systems or outdoor compressed air applications where the tubing is exposed to moisture or humidity. Always specify PA12 (not PA6) for pneumatic automation and instrument air tubing in EPC projects — the cost saving of PA6 is entirely offset by the reliability and maintenance issues from moisture-induced dimensional change.
Antistatic (AS) / Conductive Nylon Tubing
PA12 or PA11 tubing compounded with carbon black or conductive filler to achieve surface electrical resistance ≤ 10⁹ Ω per EN ISO 80079-36 — required for pneumatic tubing in ATEX Zone 1/2 and IECEx Zone 1/2 classified areas where static charge accumulation on the tube surface could generate a spark capable of igniting a flammable atmosphere. Standard (non-antistatic) PA12 has surface resistance 10¹²–10¹⁴ Ω — too high for Zone 1/2 service. Antistatic nylon tubing is typically black (from carbon black additive) or black-striped. A colour-coding convention is used in ATEX installations — verify the ATEX project colour convention before ordering. Antistatic certification per IEC 60079-0 is required for ATEX Zone 1/2 classified applications.
Polyurethane (PU) Tubing — Flexible Alternative
Thermoplastic polyurethane tubing provides maximum flexibility (smaller minimum bend radius than PA12) and excellent abrasion resistance — specified where the tubing must flex continuously (robot arm pneumatic circuits, automated assembly machine pick-and-place tubes) or where external abrasion is a concern (exposed pneumatic circuits in workshop environments). Working pressure: 10–12 bar at ambient (lower than PA12 for the same OD/wall ratio). Temperature range: −40°C to +70°C (lower max temperature than PA12). Higher cost than PA12 and lower UV resistance (yellows and becomes brittle in prolonged UV exposure). Not recommended for outdoor fixed installations — use PA12 for fixed outdoor pneumatic circuits; use PU for flexible moving connections to actuators.
Nylon Braided Hose (Textile-Reinforced)
PA12 or PA11 inner tube with a textile (polyester or aramid) braid reinforcement and a polyurethane outer jacket — providing significantly higher working pressure than unreinforced nylon tube at the same bore diameter. Braided nylon hose working pressure: 15–80 bar depending on bore size and braid construction. Used for: higher-pressure pneumatic circuits (above 16 bar working pressure); hydraulic pilot line supply (moderate pressure hydraulic circuits in mobile equipment); high-flow compressed air supply to high-speed pneumatic tools; and industrial hose assemblies requiring both flexibility and pressure resistance not achievable with unreinforced nylon tube. Per SAE J517 equivalent construction; end fittings by swage or push-lock assembly.
1.3 — PTFE Tubing Grade Classification
Virgin PTFE Tubing — Standard Grade
Extruded from unsintered PTFE (polytetrafluoroethylene) resin — the purest form of PTFE tubing with no fillers, pigments, or additives. Chemical inertness: resistant to virtually all industrial chemicals including concentrated acids (HF, HCl, H₂SO₄, HNO₃), bases (NaOH, KOH), solvents (ketones, esters, aromatics), and oxidisers — only elemental fluorine and alkali metals at high temperature attack PTFE. Temperature range: −200°C to +260°C continuous (the widest temperature range of any standard polymer tubing). Non-stick surface (μ ≈ 0.04): zero biological adhesion — essential for pharmaceutical and food process tubing where biofilm formation on the tube wall must be prevented. FDA 21 CFR 177.1550 compliant for direct food and drug contact. Zero moisture absorption: dimensionally stable in all humidity conditions.
PTFE Convoluted / Corrugated Tubing
PTFE tubing with a corrugated (accordion-fold) outer profile — the corrugations allow the tubing to flex at smaller bend radii than smooth-bore PTFE while maintaining the straight inner bore (no kinking or flow restriction at the bend). PTFE is stiffer than nylon in its smooth-bore form — convoluted PTFE provides flexibility approaching nylon while retaining all PTFE chemical and temperature properties. Used for: flexible connections to vibrating chemical dosing pumps; chemical transfer hose assemblies requiring both PTFE chemical resistance and routing flexibility; analytical instrument sample lines requiring tight routing in confined instrument rack spaces; and pharmaceutical process connections to mixing vessels where the PTFE inner bore must be maintained smooth and the hose must flex during operation.
PTFE-Lined Composite Hose
A PTFE inner tube with an outer reinforcement layer (stainless steel braiding or wire helix) and an outer protective jacket — combining PTFE chemical resistance at the fluid contact surface with the high working pressure capability of the reinforcement structure. SS-braided PTFE hose working pressure: 35–420 bar depending on bore and braid specification. SS wire-helix PTFE hose: vacuum and suction service (the SS helix prevents hose collapse under vacuum). Used for: chemical dosing hose assemblies at high pressure; offshore hydraulic supply hose in chemical plant (phosphate ester hydraulic fluid requires PTFE-lined hose — nylon and rubber degrade rapidly in ester hydraulic fluids); pharmaceutical bulk transfer hoses; and high-temperature instrumentation sample lines in refinery and petrochemical service.
Fluoropolymer Variants: FEP, PFA, PVDF
FEP (fluorinated ethylene propylene) — melt-processable fluoropolymer with chemical and temperature properties similar to PTFE but with better clarity (transparent) and easier processing; maximum continuous service temperature +200°C; lower burst pressure than PTFE at equivalent wall. PFA (perfluoroalkoxy alkane) — superior to FEP at elevated temperature (+260°C continuous); excellent purity for semiconductor and pharmaceutical ultra-pure water applications. PVDF (polyvinylidene fluoride / Kynar) — lower fluorine content than PTFE; good chemical resistance (excellent to halogens, acids, alkalis); higher tensile strength than PTFE enabling higher working pressure at thinner wall; used in chemical industry piping systems and analytical instrument flow cells. Each fluoropolymer variant requires explicit specification — “PTFE” and “FEP” are not interchangeable in procurement documents.
Conductive / Black PTFE Tubing
PTFE compound with carbon black filler to reduce surface electrical resistance to ≤ 10⁶ Ω/m — providing antistatic or static-dissipative performance for PTFE tubing in ATEX classified areas (semiconductor process equipment gas supply lines, chemical plant flammable gas instrument lines). Standard virgin PTFE has very high surface resistance (>10¹⁶ Ω) — an excellent electrical insulator that accumulates static charge during high-velocity gas flow through the tube. Black conductive PTFE discharges static safely without the ignition risk of the insulating virgin PTFE. FDA compliance of conductive PTFE: carbon black-filled PTFE may not be FDA-approved for direct food contact — verify the specific compound compliance before specifying for food-grade applications.
PTFE Spaghetti / Sleeving
Thin-wall PTFE tube used as electrical insulation sleeving for thermocouple wires, instrument signal cables, and wire bundles in high-temperature chemical plant environments. PTFE electrical insulation properties: dielectric strength 19.7 kV/mm; volume resistivity >10¹⁸ Ω·cm — excellent electrical insulation even at 200°C where most polymer insulations have already degraded. PTFE sleeving is also used as an anti-stick coating on process equipment (mandrels, forming tools) in composites manufacturing. Not to be confused with PTFE tape (thread sealant tape) — PTFE sleeving is a dimensionally controlled tube, not a tape. Available in OD 1.0 mm through 25 mm, wall thickness 0.25–2.0 mm, natural (white/translucent) and standard colours.
1.4 — Wall Thickness and Burst Pressure Calculation
t = Wall thickness (mm)
σ_UTS = Ultimate tensile strength of the tube material (MPa) — see Table 1.A below
OD = Outside diameter of the tube (mm)
WP = Working pressure (bar) — for safe continuous service
SF = Safety factor — typically 4:1 for polymer tubing (SAE J844 / ISO 14743)
Key material tensile strength values for tubing burst pressure calculation:
PA12 (Polyamide 12): σ_UTS = 48–55 MPa
PA11 (Polyamide 11): σ_UTS = 44–50 MPa
Virgin PTFE: σ_UTS = 20–30 MPa (significantly lower than PA12)
PU (Polyurethane): σ_UTS = 35–50 MPa
PVDF (Kynar): σ_UTS = 50–55 MPa
P_burst = 2 × 1.5 × 50 / 10 = 15 bar (using σ_UTS = 50 MPa midpoint)
Working pressure (SF = 4:1): WP = 15 / 4 = 3.75 bar (published rating ≈ 12–16 bar at ambient — manufacturer tests from burst data)
Note: Published working pressure ratings from tube manufacturers incorporate empirical safety factors from hydrostatic burst testing per ISO 1167 — always use the manufacturer’s published working pressure table, not a simple Barlow calculation, as the primary specification reference. Barlow’s formula is useful for comparing grades and understanding the pressure rating sensitivity to wall thickness changes.
Submit your OD, wall thickness, material grade, working pressure, colour, and quantity for a documented RFQ within 24 hours.
Working Pressures
& Standards Compliance
Nylon and PTFE tubing dimensions, working pressures, and quality requirements are governed by ISO 14743, SAE J844, DIN 74324, and manufacturer’s dimensional series. All applicable standards are supported at RR Hydraulic.
Submit OD, wall, material, colour, length, and quantity to sales@rrhydraulics.com for a certified offer.
2.1 — PA12 Nylon Tubing Working Pressure Reference
| OD (mm) | Wall (mm) | ID (mm) | WP at 20°C (bar) | WP at 60°C (bar) | Min Burst 20°C (bar) | Push-In Fitting Range |
|---|---|---|---|---|---|---|
| 4 | 1.0 | 2.0 | 16 | 10 | 64 | 4 mm push-in fittings |
| 6 | 1.0 | 4.0 | 14 | 9 | 56 | 6 mm push-in fittings |
| 8 | 1.0 | 6.0 | 12 | 8 | 48 | 8 mm push-in fittings |
| 8 | 1.5 | 5.0 | 16 | 12 | 64 | 8 mm push-in fittings |
| 10 | 1.0 | 8.0 | 10 | 7 | 40 | 10 mm push-in fittings |
| 10 | 1.5 | 7.0 | 16 | 12 | 64 | 10 mm push-in fittings |
| 12 | 1.5 | 9.0 | 14 | 10 | 56 | 12 mm push-in fittings |
| 16 | 2.0 | 12.0 | 12 | 9 | 48 | 16 mm push-in fittings |
| ¼” (6.35) | 0.89 | 4.57 | 17 | 11 | 69 | ¼” push-in / compression |
| ⅜” (9.53) | 1.24 | 7.04 | 14 | 10 | 57 | ⅜” push-in fittings |
2.2 — PTFE vs Nylon PA12: Key Properties Comparison
| Property | PA12 Nylon | PTFE (Virgin) | PU (Polyurethane) | PVDF (Kynar) | Engineering Decision Guidance |
|---|---|---|---|---|---|
| Tensile strength (MPa) | 48–55 | 20–30 | 35–50 | 50–55 | PA12 and PVDF highest WP for given wall |
| Max service temp (°C) | 80 continuous | 260 continuous | 70 | 130 | PTFE mandatory above 100°C |
| Chemical resistance | Good (oils, fuels) | Excellent (universal) | Fair (limited) | Very Good | PTFE for aggressive chemicals; PA12 for air/oil |
| Flexibility (bend radius) | Good | Poor (rigid; convoluted = better) | Excellent | Fair | PU for robot/flex; PA12 for fixed runs |
| Moisture absorption (%) | ≤ 0.25 | 0 (zero) | 0.5–1.0 | 0.04 | PA12 and PTFE stable in wet environments |
| Friction coefficient (μ) | 0.3–0.4 | 0.04 | 0.5–0.7 | 0.1–0.2 | PTFE for flow-sensitive or anti-stick applications |
| FDA food contact | Cond. (FDA grade) | Yes (21 CFR 177.1550) | Cond. | Yes | PTFE and PVDF preferred for food/pharma |
| Cost relative to PA12 | 1× (baseline) | 4–10× | 1.2–1.5× | 3–5× | PA12 standard; PTFE only where required |
| Push-in fitting compatible | Yes (all) | Limited (special PTFE fittings) | Yes | Limited | PA12 for push-in automation; PTFE for compression |
2.3 — Applicable Standards and Compliance Framework
ISO 14743
Pneumatic fluid power — push-in connectors for thermoplastic tubing. While primarily a connector standard, ISO 14743 defines the tubing OD dimensions and tolerances that thermoplastic tubing (PA12, PA11, PU) must conform to for use with push-in connectors — the OD tolerance is ±0.1 mm (e.g., 10 mm OD = 9.9–10.1 mm). This tight OD tolerance is the critical specification for pneumatic automation tubing — tubes with OD outside this range will not achieve reliable collet engagement in push-in fittings. Always specify PA12 tubing to ISO 14743 OD dimensional tolerance for pneumatic automation applications. Non-ISO tubing (wider OD tolerances) may appear cheaper but causes field installation problems and premature fitting failures.
SAE J844
Nonmetallic Tubing for Automotive Fluid Piping Systems — the dominant standard for PA11 automotive brake and fuel tubing in the US market. SAE J844 defines: dimensional tolerances (OD and ID); burst pressure requirements; flexural modulus; chemical resistance (brake fluid, fuel, lubricants); and cold temperature flexibility (bend test at −40°C). Used by automotive manufacturers worldwide for brake line tubing (SAE J844 Type B PA11) and fuel line tubing (SAE J844 Type A PA12). EPC projects referencing automotive component standards (e.g., mobile equipment hydraulic pilot lines) may cite SAE J844 for nylon tubing — verify whether the SAE J844 or ISO 14743 dimensional series applies to the specific project fittings.
DIN 73378 / DIN 74324
DIN 73378: Nylon Tubing — the German standard for PA tubing dimensions used in European automotive and industrial applications. DIN 74324: Connectors for Nylon Tubing — the companion connector standard. DIN 73378 and ISO 14743 tubing dimensions are generally compatible in the overlapping size range (4–16 mm OD), but small differences in OD tolerance classes exist — verify the specific dimensional series when mixing DIN and ISO components. German and European industrial automation projects typically reference DIN 73378 for nylon tubing; this is being progressively harmonised with ISO 14743 but both standards remain in use on active EPC projects.
FDA 21 CFR 177.1550
US Food and Drug Administration regulation governing PTFE resin for use in food-contact applications — confirms that pure PTFE polymer (without restricted additives) is permitted for direct food and drug contact. Relevant for: PTFE tubing in food processing fluid transfer; pharmaceutical bulk transfer hoses; medical device fluid paths; and beverage production lines. The FDA compliance certification covers the PTFE resin compound used to extrude the tube — not all PTFE grades are FDA-compliant (especially filled or compounded grades). Always verify the specific PTFE tube grade’s FDA compliance with the tube manufacturer before specifying for food, beverage, or pharmaceutical contact applications.
ISO 1167 (Pressure Testing)
Thermoplastics pipes, fittings and assemblies for the conveyance of fluids — Determination of the resistance to internal pressure. The standard hydrostatic burst pressure test method for polymer tubing. ISO 1167 Part 1 (pipes) and Part 2 (fittings and assemblies) define the test procedures for short-term burst pressure (minutes to failure at elevated pressure) and long-term hydrostatic strength (regression analysis for 50-year pressure rating). Published working pressure ratings for PA12 and PTFE tubing are derived from ISO 1167 burst test data at the stated safety factor. Demand ISO 1167 test records from the tubing manufacturer for project-critical supply where the working pressure rating must be formally verified.
RoHS / REACH (EU Regulations)
RoHS (Restriction of Hazardous Substances, EU Directive 2011/65/EU) and REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals, EU Regulation 1907/2006) govern the chemical composition of polymer tubing placed on the European market. RoHS restricts lead, mercury, cadmium, hexavalent chromium, PBB, and PBDE in electrical and electronic equipment — relevant for nylon tubing used in electrical wiring conduit and electronic equipment cooling. REACH restricts SVHCs (Substances of Very High Concern) in polymer compounds. Most standard PA12 and PTFE tubing grades are RoHS and REACH compliant — demand the Declaration of Conformity from the tubing manufacturer for European EPC project supply where RoHS/REACH compliance documentation is a project contractual requirement.
IEC 60079 / ATEX (Antistatic Grades)
IEC 60079-0 (Explosive Atmospheres — General Requirements) and ATEX Directive 2014/34/EU govern tubing installed in explosive atmosphere classified zones. Standard PA12 tubing is an electrical insulator (surface resistance 10¹²–10¹⁴ Ω) — accumulates static charge during high-velocity pneumatic flow, creating a spark ignition risk in Zone 1/2 gas atmospheres. Antistatic PA12 tubing (surface resistance ≤ 10⁹ Ω per IEC 60079-0 / EN ISO 80079-36) is mandatory for pneumatic tubing in ATEX Zone 1/2 areas. The tubing manufacturer’s antistatic certification must confirm the surface resistance measurement method, the test conditions, and the acceptance threshold. Demand the antistatic certification documentation for any nylon tubing specified in ATEX Zone 1/2 classified pneumatic systems.
ISO 8573-1 (Air Purity)
Compressed air — contaminants and purity classes. The air quality in the pneumatic system influences the tubing material selection and service life. ISO 8573-1 Class 1.4.1 (clean dry instrument air: particles ≤ 0.1 µm, pressure dew point ≤ −20°C, oil ≤ 0.01 mg/m³) is compatible with PA12 tubing. Wet, oil-contaminated air (Class 3-5 moisture and oil classes) causes: PA12 swelling at high moisture levels over time; accelerated PA12 degradation from petroleum oil additives at elevated temperature; and PTFE tubing is unaffected by wet or oil-contaminated air. For humid or oil-contaminated compressed air systems: prefer PTFE over PA12 tubing for long service life. For clean dry instrument air per ISO 8573-1 Class 1.4.1: PA12 is the standard specification.
Colour Coding
& Installation Guidelines
Nylon and PTFE tubing are manufactured by continuous extrusion — the material properties and dimensional tolerances are controlled by the extrusion process parameters. RR Hydraulic supplies tubing from qualified manufacturers with full material data sheets, dimensional certificates, and pressure test records.
3.1 — Extrusion Manufacturing and Quality
3.1.1 — Nylon (PA12) Extrusion
PA12 tubing is extruded on a single-screw extruder through a precision annular die — the die gap controls the wall thickness; the die bore controls the OD. After exiting the die, the hot tube is pulled through a calibration sleeve (sizing tube) in a water cooling bath — the calibration sleeve defines the finished OD to the ±0.1 mm tolerance required for push-in fitting compatibility. Wall thickness is controlled by the haul-off speed relative to the extrusion output rate — if haul-off speed increases relative to output, the wall thins; if it decreases, the wall thickens. In-line OD measurement by laser gauge provides continuous feedback to the haul-off speed controller, maintaining the OD within tolerance throughout the production run.
3.1.2 — PTFE Extrusion (Ram Extrusion)
PTFE cannot be melt-extruded (it decomposes before melting) — PTFE tubing is manufactured by ram (paste) extrusion: PTFE powder is mixed with a volatile lubricant (extrusion aid), preformed into a billet, and ram-extruded through a die at high pressure (200–500 bar) to form a tube. The extruded tube is then sintered (heated to 365–380°C) to fuse the PTFE particles and remove the extrusion lubricant, producing a smooth-bore, fully dense PTFE tube. The sintering process and cool-down rate influence the PTFE crystallinity and hence the tubing mechanical and chemical properties — virgin PTFE sintered under controlled conditions produces the highest purity, highest density, and best chemical resistance of any PTFE grade.
3.1.3 — Colour Coding for Pneumatic Systems
| Colour | Common Use (ISO / Industrial Convention) | Notes |
|---|---|---|
| Blue | Compressed air supply / main air line | Most common for general air supply in European and international pneumatic automation |
| Black | Antistatic / ATEX-rated tubing; vacuum lines | Black = carbon-filled antistatic grade in most automation conventions |
| Red | High-pressure air / emergency stop circuits | Used for higher-pressure supply circuits; also emergency air in some systems |
| Yellow | Exhaust / return / pilot exhaust signal | Exhaust port connections on directional valves; pilot return circuits |
| Green | Instrument air / clean air / special services | Used for instrument quality air separation from general plant air |
| White / Natural | Food-grade; pharmaceutical; general use | White PA12 = food-grade or pharmaceutical grade in some company standards |
| Grey | Nitrogen; inert gas; vacuum lines | Nitrogen and inert gas service distinction in chemical plant pneumatic systems |
| Orange | Hydraulic pilot / hydraulic return | Hydraulic pilot line distinction from pneumatic lines in mixed pneumatic/hydraulic systems |
3.2 — Installation Guidelines
Minimum Bend Radius
Nylon PA12 tubing minimum bend radius: approximately 5–8× OD (for 10 mm OD = 50–80 mm minimum bend radius). Kinking (flattening at the bend) occurs below the minimum bend radius — a kinked tube has reduced flow area at the kink and a stress concentration that progressively cracks the tube wall under pressure cycling. Use spring guards (PA12 coil springs slipped over the tube at the bend) to prevent kinking at tight bend locations. PTFE tubing minimum bend radius: significantly larger than PA12 (PTFE is stiffer) — typically 10–15× OD. For tight bends with PTFE: use convoluted PTFE (corrugated profile) which achieves bend radii approaching PA12 straight tube.
Tube Cutting — Clean Square Cut Essential
Always cut nylon and PTFE tubing with a tube cutter (rotary blade cutter) or a sharp single-stroke tube scissors — never with a hacksaw, knife, or serrated blade. A hacksaw produces a burr and swarf inside the tube bore that contaminates the pneumatic system and can block the collet teeth in a push-in fitting. A serrated blade produces a non-square cut face — the off-square face causes an uneven root gap inside the push-in fitting collet zone, reducing the effective seal length and pull-out resistance. A clean, square, burr-free cut is the single most important installation step for push-in fitting reliability — every tube end before insertion must be visually inspected for squareness and freedom from burrs.
Push-In Fitting Insertion Depth
The tube must be inserted into the push-in fitting to the full engagement depth — the tube end must reach the fitting body stop at the bottom of the collet zone. Partial insertion (tube end not reaching the body stop) reduces the collet engagement length and decreases the pull-out force below the minimum specified by ISO 14743. Mark the required insertion depth on the tube before insertion (mark a ring at 25–30 mm from the cut end; after insertion, the mark should be just outside the fitting body). Verify engagement depth on each fitting installation — the most common push-in fitting assembly error is incomplete tube insertion, which causes the tube to pull out under system pressure.
Temperature De-Rating of Working Pressure
Nylon PA12 working pressure must be de-rated at elevated temperature — PA12 softens above 60°C and the burst pressure decreases significantly: typical de-rating factor = 0.75 at 60°C (12 bar → 9 bar effective WP); 0.50 at 80°C (12 bar → 6 bar effective WP). Never use standard PA12 tubing for fluid service above 80°C — use PTFE, PVDF, or metal tubing instead. For steam condensate drain lines near steam traps (surface temperature 100–120°C): PTFE tubing is mandatory — PA12 will soften and collapse at these temperatures. For outdoor pneumatic systems in hot climates (surface temperature of sun-exposed tubing can reach 60–80°C): verify the derated working pressure against the system design pressure before specifying PA12.
UV Resistance and Outdoor Service
Standard natural (translucent/white) PA12 tubing has limited UV resistance — prolonged UV exposure causes surface chalking and embrittlement within 2–5 years of outdoor service in direct sunlight. For outdoor fixed pneumatic installations: specify UV-stabilised PA12 (typically dark blue or black — the UV stabiliser additive is incorporated in the pigmented compound). Black PA12 tubing provides the best UV resistance (carbon black is an excellent UV absorber) but black is also the antistatic convention — confirm with the project specification whether black tubing must be antistatic grade or standard UV-stabilised grade. Standard PU tubing has poor UV resistance and should not be used for fixed outdoor pneumatic circuits without UV protection.
PTFE Tubing Installation Specifics
PTFE tubing is not compatible with standard push-in pneumatic fittings — the PTFE OD is typically within tolerance, but the slippery PTFE surface (μ = 0.04) does not provide sufficient friction for the collet teeth to maintain the required pull-out force against internal pressure. PTFE tubing is installed using: compression fittings (ISO 8434-1 / Swagelok equivalent — the ferrule bites into the soft PTFE OD); PTFE-specific push-in fittings with serrated collet teeth designed for slippery PTFE surfaces; or flared PTFE tube ends with a support sleeve inside the PTFE bore to prevent the tube from collapsing under the flaring force. Always verify fitting compatibility with the PTFE tubing OD and wall before ordering — not all compression fitting series provide a reliable seal on thin-wall PTFE.
Industry Applications
& Documentation
RR Hydraulic maintains full traceability from certified polymer resin to finished tubing coils and cut lengths. OD gauging, wall thickness, pressure testing, material data sheet verification, and complete export documentation are standard on all project-grade nylon and PTFE tubing supply.
4.1 — Inspection & QC Protocol
4.2 — Documentation Package Reference
| # | Document | Standard / Format | Mandatory / Conditional | Notes |
|---|---|---|---|---|
| 01 | Material Data Sheet (MDS) | Manufacturer’s MDS per resin grade | Mandatory — all project tubing | UTS, elongation, temp range, chemical resistance, density |
| 02 | OD Dimensional Certificate | ISO 14743 ±0.1 mm per reel | Mandatory — push-in fitting service | Reel number cross-referenced to measured OD range |
| 03 | Wall Thickness Report | Ultrasonic measurement per lot | Mandatory — all project tubing | Min/max wall at 3 positions per reel |
| 04 | Hydrostatic Burst Test Certificate | ISO 1167 per lot sample | Mandatory — working pressure verification | Burst pressure ≥ 4× published WP; specimen data |
| 05 | Antistatic Certificate | IEC 60079-0 surface resistance ≤ 10⁹ Ω | Mandatory — ATEX Zone 1/2 supply | Every reel; humidity condition; test method |
| 06 | FDA Compliance Declaration | 21 CFR 177.1550 (PTFE) / 177.1500 (Nylon) | Mandatory — food/pharma/medical | Resin compound specific; not batch-specific |
| 07 | RoHS / REACH Declaration | EU 2011/65/EU; EU 1907/2006 | Mandatory — European EPC projects | Compound-specific; SVHC list confirmation |
| 08 | Cold Flexibility Test Report | Per SAE J844 / DIN 73378 method | Conditional — cold service ≤ −20°C | Test temperature, mandrel diameter, pass/fail |
| 09 | Colour Verification Record | Pantone / RAL reference on lot label | Conditional — ATEX colour convention; system coding | Colour code confirmed vs project pneumatic colour convention |
| 10 | First Article Inspection (FAI) Report | Project-specific format | Mandatory — new project specifications | All parameters; before bulk production |
| 11 | ISO 9001:2015 Certificate | Third-party QMS — tubing manufacturer | Mandatory — EPC projects | Scope covers PA12 / PTFE extrusion and QC |
| 12 | Country of Origin + Packing List | Chamber of Commerce / item-level | Mandatory | HS tariff code; reel length and reel count per item |
| 13 | Commercial Invoice + Bill of Lading | Per INCOTERMS 2020 | Mandatory | Freight forwarder issued |
4.3 — Applications by Industry
EPC Instrument Air and Pneumatic Control Systems
PA12 blue tubing (ISO 14743, OD 6–12 mm, wall 1.0–1.5 mm) is the standard for instrument air distribution to control valve actuators, solenoid valves, pneumatic positioners, and instrument air supply headers throughout EPC Oil & Gas, Power Generation, and Petrochemical process plants. The ISO 14743-compliant OD tolerance (±0.1 mm) ensures reliable push-in fitting collet engagement across all instrument air tubing connections. For offshore topside instrument air: antistatic black PA12 (IEC 60079-0 compliant, surface resistance ≤ 10⁹ Ω) in ATEX Zone 2 classified instrument areas; standard blue PA12 in unclassified areas. UV-stabilised blue PA12 for outdoor exposed instrument air lines on platforms and in plant areas exposed to direct sunlight.
PTFE Chemical Injection and Transfer Lines
Virgin PTFE tubing (OD 6–12 mm, natural/white) for chemical injection lines carrying corrosion inhibitors, scale inhibitors, biocides, methanol, glycol, and acid/caustic in Oil & Gas and offshore process applications. PA12 tubing cannot be used for most chemical injection fluids — the chemicals attack PA12 at varying rates depending on concentration and temperature. PTFE’s universal chemical inertness makes it the default specification for all chemical injection pump outlet lines, injection quill supply tubing, and chemical sampling system transfer tubes. PTFE compression fittings (Swagelok type, SS 316 body) for all PTFE chemical injection connections — verify tube OD and wall compatibility with the specific SS 316 compression fitting ferrule before assembly to ensure adequate ferrule bite on the softer PTFE wall.
Food, Pharmaceutical, and Ultra-Pure Applications
Virgin PTFE tubing (FDA 21 CFR 177.1550 compliant, Ra ≤ 0.4 µm electropolished bore) or food-grade PA12 (FDA 21 CFR 177.1500) for food and pharmaceutical process fluid transfer, CIP cleaning solution lines, product contact tubing in filling machines, and ultra-pure water (UPW) distribution in semiconductor fabrication facilities. PTFE is preferred over PA12 for direct product-contact lines in pharmaceutical manufacturing because: PTFE has zero extractables (no compound migrates from PTFE into the product under GMP conditions); PTFE inner surface supports no bacterial adhesion or biofilm growth; and PTFE withstands steam sterilisation at 121–134°C without dimensional change or chemical degradation. USP Class VI biocompatibility testing certification available on request for PTFE medical device tubing supply.
Automotive Brake and Fuel Lines (PA11 / PA12)
PA11 or PA12 tubing per SAE J844 (Type B for brake; Type A for fuel) for automotive brake line and fuel line assemblies — including electric vehicle brake-by-wire hydraulic actuator supply lines. PA11 (SAE J844 Type B) for brake lines: superior flexibility at −40°C (important for cold-climate vehicle operation); excellent resistance to DOT 3/4/5 brake fluids; long-term fatigue resistance under 1 million pressure cycles at up to 140 bar. PA12 (SAE J844 Type A) for fuel lines: lower moisture absorption than PA11 providing better dimensional stability at fuel fitting connections; good resistance to petrol, diesel, ethanol-blended fuels, and biodiesel at engine bay temperatures up to 80°C. Both grades require Type II outer coat (PA12 outer jacket over PA11 inner tube) for metal tank fuel system lines per SAE J30.
Gas Chromatograph and Analytical Instrument Lines
PTFE tubing (OD 1/8″ or 1/4″, SS compression fittings) for carrier gas supply (helium, hydrogen, nitrogen) to GC (gas chromatograph) columns and sample conditioning system tubing at analytical instrument racks. PTFE is mandatory for GC carrier gas tubing because: any extractable from polymer tubing contaminates the carrier gas and creates ghost peaks in the GC chromatogram; PTFE’s zero extractables prevents this contamination; and PTFE’s smoothness prevents sample adsorption at the inner bore surface (critical for trace analysis). For hydrogen carrier gas (explosive, high permeation risk through polymer walls): verify that the PTFE wall thickness and system operating pressure are within the hydrogen permeation-safe envelope — thin-wall PTFE in hydrogen service can accumulate hydrogen in the outer braid or insulation layers creating an explosion risk at the fitting connections.
Hydraulic Pilot Line and Low-Pressure Hydraulic Circuits
PA12 orange tubing (OD 6–10 mm, wall 1.5 mm, working pressure 12–16 bar) for hydraulic pilot line supply to directional control valves in mobile equipment, offshore crane hydraulic circuits, and industrial machinery hydraulic control circuits. The hydraulic pilot pressure (typically 15–40 bar in most mobile hydraulic systems) is within the PA12 working pressure range for wall thicknesses of 1.5–2.0 mm. For higher-pressure hydraulic circuits (above 40 bar pilot pressure): use nylon-braided hose (SAE 100R7/R8 equivalent) or stainless tubing with compression fittings. Always verify the hydraulic fluid compatibility with PA12 — petroleum mineral oil is compatible; water-glycol hydraulic fluid is compatible; phosphate ester hydraulic fluid (Fyrquel, Skydrol) is NOT compatible with PA12 — use PTFE-lined hose for phosphate ester hydraulic pilot lines.
4.4 — Export Packaging Specification
- Nylon PA12 and PTFE tubing wound on standard plastic reels (25 m, 50 m, 100 m per reel depending on OD) or cut to length — each reel clearly labelled with OD, wall thickness, material grade, colour, reel length, batch number, and ISO 14743 OD conformance status
- Reel ends sealed with plastic plugs in both tube bores before packaging — prevents moisture, dust, and contamination from entering the tube bore during shipping and storage. PTFE tubing bore plugs must be clean plastic (not carbon steel or rubber) — contamination of the clean PTFE inner bore at the tube ends is an installation problem that cannot be easily remedied after receipt
- Antistatic PA12 tubing (black, ATEX grade): packaged in ESD-safe bags or ESD-safe reel wrappers — the antistatic performance must be preserved during transit; standard plastic packaging generates static which temporarily reduces the surface resistance of the outer jacket, causing a false reading if surface resistance is re-tested immediately after removing packaging. Allow 30 minutes for the tube surface to equilibrate before conducting acceptance surface resistance testing at the destination
- PTFE tubing wound on larger-radius reels than PA12 (PTFE is stiffer — minimum coiling radius 50× OD vs 15× OD for PA12) — do not over-constrain PTFE on small reels as this causes permanent set at the inner coil radius, creating a non-straight tube on deployment that is difficult to route
- Cut-to-length tubing: ends capped, bundles per OD and material tied with non-metallic ties (PA12) or stainless wire ties (PTFE), bundled in polybag or paper wrap with full identification label on each bundle
- ISPM-15 timber or cardboard export cartons for reel shipments; inner reel-to-reel foam or cardboard separators to prevent colour contamination and physical reel damage during ocean freight; desiccant sachets for PTFE tubing in humid destinations; documentation in waterproof pocket: MDS, OD certificate, wall thickness report, burst test certificate, antistatic certificate (ATEX lots), FDA compliance declaration (food/pharma lots), RoHS/REACH declaration, FAI report
4.5 — ISO and Quality System Compliance
ISO 9001:2015
Quality Management System at the tubing manufacturing facility covering: resin procurement and batch traceability; extrusion process qualification (die temperature profile, haul-off speed, calibration bath temperature, cooling rate); in-line OD laser gauge calibration and control; wall thickness ultrasonic measurement procedure; burst pressure test procedure per ISO 1167; antistatic surface resistance test procedure per IEC 60079-0; visual inspection procedure; reel winding and packaging controls; and full traceability from raw resin batch to dispatched reel. Mandatory for EPC, offshore, food-grade, and ATEX-rated tubing procurement from RR Hydraulic’s qualified manufacturer partners.
ISO 14743 / ISO 6945
ISO 14743 governs the tubing OD and wall dimensional tolerance for pneumatic push-in fitting compatibility — the ±0.1 mm OD tolerance is the defining requirement. ISO 6945 (Rubber and plastics hoses and hose assemblies — determination of resistance to ozone under static conditions) is referenced for the UV and ozone weathering resistance of outdoor PA12 and PU tubing. For EPC projects specifying outdoor pneumatic tubing: demand the ISO 6945 ozone resistance certification for UV-stabilised PA12 to confirm the UV stabiliser compound provides adequate ozone resistance for the outdoor service environment. Standard (non UV-stabilised) PA12 will crack in outdoor ozone exposure within 2–3 years in industrial environments — UV-stabilised or carbon-black pigmented PA12 provides 10+ years outdoor service life.
IEC 60079 / ATEX 2014/34/EU
ATEX Directive 2014/34/EU and IEC 60079 series govern equipment and protective systems for explosive atmospheres — including pneumatic tubing in classified zones. For nylon pneumatic tubing in ATEX Zone 2: antistatic grade (surface resistance ≤ 10⁹ Ω) is required per EN ISO 80079-36 (category 3 equipment). For ATEX Zone 1: low-resistance antistatic or conductive tubing (≤ 10⁶ Ω) may be required depending on the specific gas group and category — verify with the ATEX system design engineer. The ATEX product certification for antistatic nylon tubing must include the zone classification (Zone 1 or Zone 2), equipment group (IIA/IIB/IIC), and temperature class (T1–T6) for which the tubing is approved — a Zone 2 approval alone is not sufficient for Zone 1 installation.
USP Class VI / EN ISO 10993
For PTFE and food-grade nylon tubing in pharmaceutical and medical device applications: USP (US Pharmacopeia) Class VI biocompatibility testing confirms that the material and its extractables do not produce biological reactions (systemic injection test, intracutaneous test, implant test) — the highest level of USP plastic biocompatibility classification. EN ISO 10993 (Biological evaluation of medical devices) is the international equivalent. USP Class VI certification is required by pharmaceutical cGMP guidelines for any polymer in direct product contact. PTFE is typically already USP Class VI compliant by material nature — verify the specific compound certification with the manufacturer. For pharmaceutical-grade PA12 tubing: the plasticiser and stabiliser additives in the compound must also be USP-compliant; standard industrial PA12 may not meet USP requirements without reformulation.
Submit your OD, wall thickness, material, colour, working pressure, and quantity to RR Hydraulic for a complete, certified commercial offer.