The SENGA Pneumatic Fitting Guide
In industrial pneumatics, a pneumatic fitting or pneumatic connector is a mechanical link that allows the passage of a fluid (compressed air, vacuum, gas, water, oil, etc.) without leakage within a circuit. Fittings are used to connect or disconnect tools (compressor, sander, impact spanner, screwdriver, blow gun, cylinder etc.) or hoses/tubes in a simple and fast way while resisting the working pressure and ensuring the required flow rate for a given application.
Pneumatic fittings are intended for professionals in the food, pharmaceutical, medical and chemical industries, industrial maintenance, transport (railways, heavy goods vehicles), car garages, special machines, etc...
SENGA, a specialist in pneumatic fittings for over 40 years, offers one of the widest ranges of fittings on the market and is interchangeable with most of the competition's products. Our range includes :
- Universal compression fittings
How to choose a pneumatic fitting for a given application?
- The nature of the fluid: compressed air, gas, vacuum, water, oil, solvent, lubricant, grease, brake fluid or coolant...
- The operating temperature: expressed in degrees Celsius (°C) or Kelvin (K).
- Working pressure: expressed in bar, Pa or PSI or vacuum resistance/level expressed in bar, Pa, PSI or Hg.
- The working environment and atmospheric conditions: aggressive, chemical, explosive, humidity, presence of solvents, risk of corrosion, saline environment, etc.
- Standards to be respected: FDA, NSF, ACS, RoHS, REACH, CE, DIN, NF E, ATEX fire standard, etc.
- The material of the fitting: technopolymer, zamac, nickel-plated or raw brass, brass or POM for foodstuffs, 316L stainless steel, galvanised steel, etc.
- The seal: the material of the seal must be carefully chosen; NBR for the most common applications, Viton/FKM/FPM for high temperatures, EPDM for food applications. We also offer sealing washers (bi-material, aluminium or PA), pre-stressed conical fittings, PTFE rollers or sealing glue for BSPP threads.
- The connection/disconnection system: push-in, push-on, universal compression, express.
- The standard of the thread: cylindrical BSP (British Standard Pipe Parallel "BSPP") indicated by the letter G or conical BSP (British Standard Pipe Taper thread "BSPT") indicated by the letter R with cone to edge seal, metric (M) or "NPT" (National Pipe Tapered).
- The second connection of the fitting: male or female thread, splined sleeve, bulkhead, spring...
- The diameter and size of the thread: in order to optimise the flow and limit pressure drops.
- The available space for the application: compact, miniature, normal series...
- The swivel capability of the fitting body/threaded base: useful for applications with a small footprint.
- The nature and calibration of the pipe/tube to be connected: polyamide (PA), polyurethane (PU), polyethylene (PE), fluoropolymer (PVDF kynar, PTFE, FEP), ALPE, Nylon PA6.6, silicon, braided PVC, soft cloth, copper, stainless steel, aluminium...
The different types of pneumatic fittings
I) Push-in fittings
Instant fittings are characterised by an extremely simple system for attaching the tube. The tube is simply pushed into the fitting. To disconnect, the ring is pushed in and the tube is pulled out:
a)2800 series - Push-in fittings in resin 
- Field of application: compressed air and vacuum
- Vacuum resistance : - 99 KPa
- Maximum working pressure: 16 BAR
- Working temperature: -20°C / +70°C
- Materials: acetalic resin (POM) body, nickel-plated brass base, NBR seal
b) 4600 series - Push-in fittings mini series 
The 4600 miniature series is used for small diameter pneumatic hose types.
Features
- The miniature range has 40% less volume and 20% less outer diameter than a conventional plastic range.
- The nickel-plated brass installation fittings have excellent corrosion resistance.
The elliptical plunger in Ø 3 assists in the easy removal of the tube in a confined space.
- Materials: nickel-plated brass, NBR seal
- Application range: compressed air, vacuum
- Pressure range 0-150 PSI 0-10 BAR (0-900 kPa)
- Negative pressure -29.5 in Hg -750 mmHg
- Working temperature 32 - 140° F 0 - 60° C
- Tube Type Polyamide / Polyurethane / Nylon
c) SISTEM - Push-in fittings in nickel plated zamak 
- Field of application: compressed air
- vacuum resistance : - 99 KPa
- maximum working pressure: 16 BAR
- working temperature: - 10°C / +80°C
- Materials: nickel-plated zinc diecast body, NBR seal
d) 4200 - Push-in fittings in POM for food industry 
Our 4200 Series fittings are designed for water, food, and compressed air but can be used for certain gases, vacuum and other liquids.
A single action allows the tube to release and connect easily.
These fittings are manufactured to NSF standards, (non-toxic and approved materials).
Use may differ depending on the user's environment and application.
- Application range: water, beverages, compressed air, gases and compatible liquids
- Materials: POM, EPDM seal
- Standards: NSF 51.61, FDA, RoHS 2, REACH, ACS, DM 174/2004, CE 1935/2004
Pressures (NSF standards) :
- Minimum pressure: - 0.99 bar
- Maximum working pressure: 20 bar (Ø 4 - 6 - 8)
14 bar (Ø 10 - 12)
Temperature (variable according to fluids) :
- Minimum temperature: - 20°C
- Maximum temperature: + 98°C
Recommended pipes :
- Tubes in plastic materials:
- Polyamide, PTFE, food grade polyethylene,
- Polyurethane, etc...
e) 1900 - Push-in fittings in brass for food industry 
The 1900 range has been awarded the NSF-169 certificate. This certificate is your assurance that these products have been examined by an independent and reputable body and confirmed as being suitable for use in contact with food up to 95°C.
Standard: NSF/ANSI-169
Materials: NSF-169 approved galvanic process nickel plated brass body, food grade FKM seal
Pressures:
- Minimum pressure: - 0.99 bar (- 0.099 Mpa)
- Maximum pressure: 15 bar (1.5 Mpa)
Temperature :
- Minimum temperature: -15°C
- Maximum temperature: + 190°C
Thread: Cylindrical gas according to ISO 228 class A
Recommended pipes -> Plastic pipes: PA6, PA11, PA12, PTFE, Polyethylene, Polyurethane 98 shore A, etc...
Compatible fluids: Compressed air, vacuum, steam, water
f) 5800 - Push-in fittings in stainless steel 
- Field of application: chemical and food industry
- Vacuum resistance : -0.99 BAR
- Maximum working pressure: 15 BAR
- Working temperature: - 20°C / + 150°C
- Materials: AISI 316L stainless steel body, FPM seal
g) 5950 - Miniature stainless steel push-in fittings 
- Field of application: chemical and food industry
- Vacuum resistance : -0.99 BAR
- Maximum working pressure: 18 BAR
- Working temperature: - 20°C / + 150°C
- Materials: AISI 316L stainless steel, FKM seal
- Features: small dimensions
h) 400 - Push-in fittings for misting 
Application: Fogging for cooling, odour control, humidity control and dust suppression
Working pressure :
- Maximum pressure: 80 bar
Working temperature :
- Minimum temperature: - 20°C
- Maximum temperature: + 80°C
- Tolerances on tubes: +/- 0.07 mm up to Ø 3/8" Recommended tube: High strength polyamide 12 (PA12HR)
- Recommended pipe: High strength Polyamide 12 (PA12HR)
- Materials: Nickel-plated brass body, NBR seal
i) 700 - Push-in fittings for high pressure 
Application range: lubrication systems, transport, heavy industry
Pressures :
- Minimum pressure: 0 bar (0 Mpa)
- Maximum pressure with fluids: 150 bar (15 Mpa)
- Maximum pressure with compressed air: 30 bar (3 Mpa)
Temperature :
- Minimum temperature: -30°C
- Maximum temperature: + 150°C
Thread: Gas tapered to ISO 7.1, BS 21, DIN 2999
Metric tapered to UNI 7707
- Compatible fluids: Oil, water, grease, compressed air
- Recommended pipe: NYLON PA6-6 high pressure
- Materials: Nickel-plated brass body, HNBR seal
- Standards: REACH 1907/2006 and RoHS 2011/65/EC
j) 7000 - Push-in fittings for braking systems 
The quick coupling type, made of brass, has been designed to be used with polyamide 11/12 or polyester elastomer tubes on pneumatic circuits of auxiliary installations and heavy-duty braking systems and trailers. It is a ready-to-use safety coupling, requiring no tools for coupling with the tube. All that is required is to manually snap the tube into the coupling housing. The assembly time is thus extremely reduced compared to traditional couplings with cutting rings. A reduction in assembly time of around 70-80% can be estimated. The tolerances of the pipes used must strictly comply with ISO 7628 and DIN 74324/73378. The temperature range of the quick coupling is -40°C/+100°C. The tightness under these conditions is guaranteed by a special mixture chosen for the O-rings.
- breakaway test: DIN 74324 (ISO 7628)
- leakage test: DIN 74324 (ISO 7628)
- salt spray test: DIN 50021 SS (ISO 21227-2)
- vibration resistance test: DIN IEC 6812-6
- TUV automotive certificate
II) Push-on fittings
Unlike push-in fittings, push-on fittings require a tightening operation (of the nut) on the pipe:
a) Push-on fittings in nickel plated brass 
- Application range: compressed air, vacuum
- Maximum working pressure: 18 BAR
- Working temperature: -18°C / + 70° C
- Materials: nickel-plated brass, NBR seal
b) Push-on fittings in stainless steel 
- Field of application: compressed air, aggressive environments, chemicals
- Maximum working pressure: 18 BAR
- Working temperature: - 40°C / + 140° C (0°C / + 140° C on swivel fittings)
- Materials: AISI 316L stainless steel, Viton FKM seals
- Standard: NSF
III) Universal compression fittings
Universal compression fittings consist of a body, a clamping nut and a ring that is pressed onto the pipe for clamping.
a) Universal double cone fittings 
- Application range: compressed air, oil, water
- Maximum operating pressure at 20°C of the connection: from 70 to 150 BAR see technical documentation table
- Working temperature: - 40°C / + 100°C
- Materials: raw brass, NBR seal
b) Universal compression fittings DIN standard in nickel plated brass 
- Application range: compressed air, oil, water
- Maximum operating pressure at 20°C of the connection: from 35 to 150 BAR see technical documentation table
- Working temperature: - 40°C / + 100°C
- Material: nickel-plated brass
c) Universal compression fittings DIN 2353 in stainless steel 
- Field of application: compressed air, oil, water, chemical, pharmaceutical, food grade
- Maximum working pressure: see table. Between 100 and 630 BAR.
- Working temperature: -150°C / +400°C
- Materials: stainless steel AISI 316 ti, FKM seal
- Standard: DIN 2353/ISO 8434-1
d) Cutting ring fittings for centralized lubrication systems 
- Field of application: lubrication, oil, water, in industrial fields, and on agricultural machines, construction equipment, utility vehicles, etc.
- Maximum working pressure depending on the model: from 100 to 250 BAR.
- Working temperature: - 40°C / + 100°C
- Material: zinc-plated steel body
- Standard: DIN 2353/ISO 8434-1
IV) Claw couplings (NF E29-573) 
- Application range: compressed air, cold water
- Maximum working pressure : 10 BAR
- Working temperature : - 10°C / + 80° C
- Built according to the NF E29-573 standard
- Distance between claws: 41 mm
- Materials: die-cast brass body (1) and black rubber seals (2)
