What is the difference between a deflagration and detonation flame arrestor?

Deflagration flame arrestors handle subsonic flame propagation (flame speed 50 pipe diameters for most gas groups). Detonation arrestors are more robustly built and tested to withstand the pressure shock of detonation waves.

How do I determine the correct MESG for my application?

MESG (Maximum Experimental Safe Gap) is a property of the gas/vapor mixture, not the arrestor. It is determined by testing per IEC 60079-20-1. Gas group IIA has MESG >= 0.9 mm (propane, gasoline vapor), IIB has 0.5-0.9 mm (ethylene, town gas), and IIC has < 0.5 mm (hydrogen, acetylene). Select a flame arrestor certified for your gas group or a lower MESG group for safety margin.

Do flame arrestors require maintenance?

Yes. Flame arrestor elements should be inspected at least annually for corrosion, plugging, or mechanical damage. In dirty or fouling service (sulfur compounds, polymer-forming vapors), more frequent inspection (quarterly) is recommended. Clean the element with appropriate solvent and compressed air. Replace the element if any crimped ribbon passages are deformed, blocked, or show signs of corrosion pitting. Always install with the flow direction arrow correctly oriented.

Can a flame arrestor be installed in any orientation?

End-of-line flame arrestors are typically installed vertically (weather hood up) to prevent rain and debris entry. In-line detonation arrestors can be installed in horizontal or vertical piping, but the flow direction must match the arrow on the housing. Some in-line models have orientation restrictions — always check the manufacturer's installation manual. Bi-directional flame arrestors are available for applications where flow direction may reverse.

In Line Breather Valve with Flame Arrester

Better resistance to corrosion, chemical attack, adhesion of liquids and vapors, extreme temperatures, etc.

10% overpressure full opening

Leakage is well below API2000 standards and guarantees high setting accuracy (±3%).

Spool assembly is field replaceable

Supports ANSI, HG/T flanges

Integrated flame retardant breather valve
FEATURES
1. The overall fire resistance performance has been tested and meets the requirements of ISO16852
2. For explosion group level IIA and IIB3 media
3. Obtain product type certification
4. Traffic maps certified by third-party authoritative organizations that comply with ISO28300 requirements
5. High sensitivity, low overpressure value 10% wing shaped valve disc technology
6. The reseating pressure is 85% of the opening pressure
7. Adopting metal surface sealing technology
8. The flame arrester is installed on the atmospheric side and can achieve online inspection, maintenance, and replacement of the flame arrester

Social and economic benefits
Under normal operating pressure of the storage tank, the VOCs emission concentration range tested on site by the valve is between 1.61-15.2 mg/m3, which meets the special limit of 20 mg/m3 for VOCs unorganized emissions in the factory area as specified in Appendix A of the “Unorganized Emission Standards for Volatile Organic Compounds” (GB37822-2019), and has significant social benefits.
2. It can save VOCs collection and treatment facilities, while significantly reducing nitrogen consumption, bringing significant economic benefits to enterprises.

End of Line Breather Valve Iwith Flame Arrester

FAQ

Q:What is a closed loop sampler and how does it work?

A closed loop sampler is a safety device used to collect liquid samples from pipelines or storage tanks without exposing operators to hazardous chemicals. Wanan closed loop samplers comply with API MPMS 8.2 standard and feature a sealed design that returns purge fluid back to the process, eliminating VOC emissions.

Q:What certifications does Wanan Technology have for flame arrestors?

Wanan flame arrestors are certified to ISO 16852, ATEX (European Explosive Atmospheres Directive), and EN 12874 standards. We provide type test reports for IIA, IIB, and IIC gas groups. All products are manufactured in our ISO 9001:2015 certified facilities.

Q:Does Wanan Technology supply to major oil companies?

Yes. Wanan Technology is a registered qualified supplier for Sinopec, PetroChina, CNOOC (China), ExxonMobil, LukOil (Russia), ENI (Italy), KazMunayGas (Kazakhstan), and PDVSA (Venezuela), among others.

Q:Where are Wanan Technology factories located?

Wanan Technology has manufacturing facilities in Germany, USA, and China. We also have inventory and sales service centers in UAE to serve Middle East and global customers with fast delivery.

Q:What scenarios are suitable for Wan'an Technology's sealed sampler?

Wan’an Technology’s closed sampler is suitable for liquid sampling scenarios involving toxic and hazardous media in petrochemical, natural gas, oil refinery, and tank farm industries. It complies with API MPMS 8.2 standards, prevents operators from coming into contact with hazardous substances, and meets HSE environmental emission requirements.

Q: What is your typical lead time for standard and customized products?

A: Standard products ship within 2-4 weeks from order confirmation. Custom-engineered solutions typically require 6-8 weeks depending on specification complexity. For urgent projects, we offer expedited production upon request — contact our sales team with your timeline and we will work out a schedule.

Q: What international certifications do your products hold, and can you provide compliance documentation?

A: Our products comply with major international standards including ISO 3170 (petroleum sampling), API MPMS 8.1/8.2, ATEX for explosive atmospheres, ASME, and EAC. DOT and TPED certifications are available for sample cylinders. We provide full certification documentation and material test certificates with every order.

Q: Can I request a sample or trial unit before placing a bulk order?

A: Yes. We offer sample units for evaluation purposes. Upon approval, we ship one or two units so you can verify compatibility with your application, materials, and site conditions before committing to a volume order. Shipping costs may apply depending on destination.

How Flame Arrestors Work

A flame arrestor is a passive safety device fitted to the vent pipe of a storage tank or process vessel that prevents the propagation of flame from the external atmosphere into the tank (end-of-line configuration) or between connected piping sections (in-line configuration). The core component is a flame element — typically a crimped metal ribbon or sintered metal matrix — with precisely engineered gaps smaller than the Maximum Experimental Safe Gap (MESG) for the target gas group.

When a flame front reaches the arrestor element, the narrow passages extract heat from the combustion gases faster than the reaction can generate it, extinguishing the flame. The element also quenches free radicals that sustain combustion. This principle is governed by ISO 16852 (international) and EN 12874 (European) standards, which define performance testing requirements including deflagration, detonation, and endurance burn testing.

End-of-line flame arrestors are installed at the vent outlet of atmospheric storage tanks storing flammable liquids. In-line detonation arrestors are installed in piping systems where flame could propagate between connected vessels. The selection depends on the gas group (IIA, IIB, IIC), the potential flame propagation mode (deflagration vs detonation), and the pipe configuration (distance from ignition source).

Key Technical Specifications

Parameter	End-of-Line	In-Line Detonation
Nominal Size	DN25 - DN300	DN25 - DN400
Gas Group	IIA / IIB / IIC	IIA / IIB / IIC
Max Operating Temp	150 C (standard); 400 C (high-temp)	150 C (standard); 400 C (high-temp)
Material	316L SS body + element	316L SS body + element
Certification	ISO 16852, ATEX, EAC	ISO 16852, ATEX, EAC
Flame Stability	Short-time burn: 2 min	Endurance burn: 2+ hours

Parameter

End-of-Line

In-Line Detonation

Nominal Size

DN25 - DN300

DN25 - DN400

Gas Group

IIA / IIB / IIC

Max Operating Temp

150 C (standard); 400 C (high-temp)

Material

316L SS body + element

Certification

ISO 16852, ATEX, EAC

Flame Stability

Short-time burn: 2 min

Endurance burn: 2+ hours

Applications by Industry

Storage Tank Venting: Installed on PVRV outlets or vent pipes of tanks storing Class I flammable liquids (flash point < 37.8 C)

Process Piping: In-line detonation arrestors in vapor recovery systems, flare lines, and interconnected vessel piping

Vapor Combustion Systems: Flame arrestors on vapor collection headers upstream of thermal oxidizers or vapor combustors

Marine Loading: Vapor recovery systems at marine terminals and loading arms

Certifications & Compliance

Wanan flame arrestors are certified to ISO 16852 (performance), ATEX Directive 2014/34/EU (explosive atmospheres), and EAC (Eurasian Conformity for CIS markets). Each unit undergoes flame transmission testing, endurance burn testing (for in-line detonation types), and hydrostatic pressure testing at 1.5x design pressure. Material certificates per EN 10204 3.1 are provided with all shipments.

In Line Breather Valve with Flame Arrester

In Line Breather Valve with Flame Arrester

Related Products

FAQ

How Flame Arrestors Work

Key Technical Specifications

Applications by Industry

Certifications & Compliance