In industries such as new-energy batteries, semiconductors, aerospace and automotive electronics, the high & low temperature test hose plays a key role in connecting the temperature chamber (high/low temperature test chamber / thermal shock chamber / constant-temperature & humidity chamber) to the device under test. In environments with a wide temperature range of -200℃ ~ +260℃, corrosive media or ultra-clean process water, ordinary metal or rubber hoses suffer from aging, cracking, metal-ion leaching and seal failure. PFA tube (perfluoroalkoxy alkane — a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether) stands out for its wide temperature range, strong acid/alkali resistance and high cleanliness, and has become one of the preferred materials for high & low temperature test hoses. This article walks through PFA tube and PFA ferrule fittings from selection criteria, performance parameters, application scenarios, leak-test verification and procurement suggestions, providing a ready-to-use selection guide.
1. Why choose PFA tube for high & low temperature test hoses
The core requirements of a high/low temperature test chamber for hose lines center on three points: ① long-term alternating operation within a wide temperature range of -80℃ ~ +200℃ (partly -196℃ ~ +260℃) without cracking; ② no metal-ion leaching and no media contamination when conveying DI water / ultrapure water / corrosive reagents; ③ reliable sealing and no leakage under strong vibration and rapid cooling/heating. The characteristics of the PFA hose assembly fit these three points highly well:
Wide temperature range: long-term service temperature -200℃ ~ +260℃, covering both liquid-nitrogen cryogenic tests and high-temperature aging tests;
Chemical resistance: resistant to strong acids (HCl, HNO₃, H₂SO₄), strong alkalis (NaOH, KOH), strong oxidizers (aqua regia, hydrogen peroxide) and almost all organic solvents;
High cleanliness: high raw-material purity, metal-ion leaching at ppb level, suitable for semiconductor-grade DI water and high-purity reagent transfer;
Non-stick & anti-fouling: inner-wall Ra ≤ 0.2 μm, low media residue, easy CIP / SIP cleaning;
Flame retardancy: UL94 V-0 rating, self-extinguishing after leaving fire, meeting the internal fire-protection requirements of test chambers.
2. Comparison of finished-hose-assembly temperature ranges for high & low temperature test hoses (PFA / PTFE / FEP / stainless steel)
| Material | Long-term service temperature
Finished hose assembly (with braid/fitting/seal) | Chemical resistance | Cleanliness | Typical application |
|---|
| PFA tube / PFA hose assembly | -200℃ ~ +260℃ | Excellent (aqua regia, strong alkali, organic solvents) | High (ppb level) | Thermal shock chamber, semiconductor wet process, strong corrosive media |
PTFE hose assembly
(PTFE base tube: -70℃ ~ +260℃) | -54℃ ~ +204℃ | Excellent | High | Mid-temperature strong corrosion; range limited by stainless-steel braid & fitting seals |
FEP tube
(mostly used as tubing, rarely as finished assembly) | -200℃ ~ +204℃ | Good | Medium | Medium temperature, general cleanliness requirements |
316L stainless steel EP tube
(depends on seal material) | -196℃ ~ +400℃ | Medium (limited Cl⁻ resistance) | Very high (SEMI F57) | Semiconductor ultrapure water, supercritical CO₂ |
Note: all temperatures in the table are the long-term service temperature of the finished hose assembly (with braid reinforcement, fittings and seals). The base-tube temperature is generally 30~50℃ wider than the finished assembly. For example, the PTFE base tube can reach -70℃ ~ +260℃, but once made into a PTFE hose assembly, limited by the stainless-steel braid and fitting seals, its range shrinks to -54℃ ~ +204℃. Therefore, for liquid-nitrogen cryogenic tests below -54℃ or high-temperature aging tests above +204℃, it is recommended to select the PFA tube + PFA ferrule fitting solution directly.
Conclusion: if a high & low temperature test hose must balance wide temperature range + strong chemical resistance + high cleanliness, the first choice is PFA tube + PFA ferrule fitting; if the media is pure ultrapure water or supercritical fluid, a 316L stainless steel EP tube may be selected; if the operating temperature falls within -54℃ ~ +204℃ and the layout is mainly static tubing, a PTFE hose assembly is sufficient and the procurement cost is lower; once the temperature is below -54℃ or above +204℃, the PTFE hose assembly exceeds its normal range and should switch to the PFA solution.
3. Key specifications & selection parameters of PFA tube
Before purchasing PFA tubes, it is recommended to confirm the following 6 parameters to avoid selection deviation:
Outer diameter × wall thickness: common 1/4"×0.062", 3/8"×0.062", 1/2"×0.062", 3/4"×0.062", 1"×0.062"; custom outer diameter 1.6 ~ 54 mm / wall thickness 0.1 ~ 3.0 mm are also available;
Working pressure: select 1.0 ~ 1.6 MPa rated-pressure tube according to the chamber loop pressure (atmospheric ~ 1.0 MPa), with a 4× safety factor reserved;
Working temperature: define the maximum / minimum temperature and the number of thermal cycles (e.g. -55℃↔+150℃ for 1000 cycles);
Media: DI water / ultrapure water / ethanol / isopropanol / strong acid / strong alkali / refrigerant (e.g. liquid nitrogen, Freon alternative);
Cleanliness: whether SEMI F57 and ppb-level metal-ion leaching are required;
Connection method: PFA ferrule fitting, PFA flare fitting, or transition to metal VCR.
4. Sealing & leak-test points of PFA ferrule fittings
The sealing reliability of PFA tubes largely depends on the design and installation of the PFA ferrule fitting (double-ferrule / flare-ferrule):
Double-ferrule structure: the front ferrule provides the initial seal, the back ferrule provides anti-vibration lock and stress buffering;
Flare fitting: metal-to-metal sealing via a 37° or 60° flare at the PFA tube end, suitable for high-cleanliness occasions;
Helium mass-spectrometer leak test: it is recommended to perform an overall helium leak test after assembly, with a leak rate better than 1×10⁻⁹ Pa·m³/s;
Installation torque: tighten according to the manufacturer's specification (e.g. 1/4" ferrule 8 ~ 10 in-lb) to avoid over-tightening that deforms the PFA tube end;
Re-assembly times: a quality PFA ferrule fitting supports ≥ 50 re-assemblies without failure, suitable for test benches that frequently adjust tubing.
5. Typical application scenarios
High & low temperature test hoses are widely used in the following scenarios:
Thermal shock chamber: connects the liquid-nitrogen / refrigerant loop with the test cavity; PFA tube resists -196℃ deep cryogenic and rapid heating alternation;
Constant-temperature & humidity chamber: DI-water humidification / dehumidification loop; PFA tube leaches no metal ions and does not contaminate water quality;
High/low temperature & humidity chamber: resists 85℃ / 85%RH long-term humidity-heat aging without cracking or delamination;
Battery high/low temperature test bench: cooling loop for battery charge/discharge cycle testing, resistant to electrolyte corrosion;
Semiconductor high/low temperature test equipment: process-gas and cooling-water loops for wafer / packaged-device temperature-cycling tests;
Automotive-component high/low temperature test: cold-start and high-temperature aging tests of sensors and ECUs.
6. KUNGFLEX high & low temperature test hose solution
As a source factory with 17 years of fluid-connector manufacturing experience and ISO 9001:2015 certification, KUNGFLEX provides complete high & low temperature test hose solutions:
PFA tube raw material uses high-purity PFA resin of the same grade as Chemours DuPont 951HP PLUS;
Regular sizes fully stocked: outer diameter 1/4" ~ 2" (6.35 ~ 54 mm), wall thickness 1.0 ~ 3.0 mm;
Equipped with PFA double-ferrule fittings, PFA flare fittings, and 316L VCR / ferrule adapters;
Non-standard customization supported: inner diameter / wall thickness / length / color (conductive / anti-static / heat-conductive) flexibly adjusted;
100% helium mass-spectrometer leak test + 5000-cycle durability test, archived and traceable.
With a 2000㎡ workshop in Nantong, Jiangsu, our own mold workshop and machining center, we provide one-stop service from selection, prototyping to batch delivery for chamber manufacturers, testing centers and research institutes.
7. Common selection questions
Q1: How many years can a PFA tube last?
Within the rated temperature range of -200℃ ~ +260℃, a quality PFA tube has a design life of ≥ 10 years; exceeding the range or long-term exposure to ultraviolet light accelerates aging and needs evaluation by working condition.
Q2: Does the thermal shock chamber hose line need helium leak testing?
Recommended. During long-term operation of thermal shock tests, micro-leaks in the line cause refrigerant loss and temperature-control drift; an overall helium leak test (1×10⁻⁹ Pa·m³/s) eliminates hidden risks before leaving the factory.
Q3: Can PFA ferrule fittings be disassembled and reassembled repeatedly?
A quality double-ferrule fitting supports ≥ 50 disassemblies without failure; after each disassembly it is recommended to re-do pressure holding or helium leak test to ensure reliable sealing.
Q4: Which is more suitable for high & low temperature testing, PFA hose assembly or PTFE hose assembly?
It depends on the operating temperature range. The normal available range of a PTFE hose assembly is -54℃ ~ +204℃, sufficient to cover most mid-temperature high/low temperature cycling tests and at lower cost; the available range of a PFA hose assembly is -200℃ ~ +260℃, and it still maintains a wide range after being paired with PFA ferrule fittings, and can be heat-fusion welded and bent long-term without easy kinking. Therefore: if the condition is within -54℃ ~ +204℃, both are selectable and PTFE hose is more economical; once it involves liquid-nitrogen cryogenic (below -54℃) or high-temperature aging above +204℃, please select the PFA hose assembly solution directly.
Q5: Can non-standard specifications and OEM/ODM be provided?
Yes. KUNGFLEX supports customizing PFA tube specifications, length, color and markings per drawing; OEM/ODM minimum order quantity starts from 50 meters.
Conclusion
Choosing the right high & low temperature test hose is the key to ensuring long-term stable operation of the chamber and reducing maintenance costs. The combination of PFA tube and PFA ferrule fitting performs prominently in wide-temperature, strong-chemical and high-cleanliness scenarios. If you need to equip your thermal shock chamber, constant-temperature & humidity chamber or battery high/low temperature test bench with KUNGFLEX PFA tube + PFA ferrule fitting, please contact the KUNGFLEX technical team (hotline 400-820-9728 / 13764595878) for selection support and samples.
Author: KUNGFLEX Technical Team · Last updated: 2026-09-02 · Applicable: KUNGFLEX PFA tube & PFA ferrule fitting series · Sources: ISO 9001:2015 quality system, SEMI F57, ASTM D3307 / D6867 and other public standards and manufacturer technical data.
