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What is a Safety Valve?

The primary purpose of a safety valve is the protection of life, property and environment. A safety valve is designed to open and relieve excess pressure from vessels or equipment and to reclose and prevent the further release of fluid after normal conditions have been restored. There are number of reasons why the pressure in a vessel or system can exceed a predetermined limit. API Standard 521/ISO 23251 Sect. 4 provides a detailed guideline about causes of overpressure. The most common are:

  • Blocked discharge
  • Exposure to external fire, often referred to as “Fire Case”
  • Thermal expansion
  • Chemical reaction
  • Heat exchanger tube rupture
  • Cooling system failure

Each of the above listed events may occur individually and separately from the other. They may also take place simultaneously. Each cause of overpressure also will create a different mass or volume flow to be discharged, e.g. small mass flow for thermal expansion and large mass flow in case of a chemical reaction. It is the user’s responsibility to determine a worst case scenario for the sizing and selection of a suitable pressure relief device.

LESER offers spring loaded and pilot operated safety valves for all industrial applications according to the Pressure Equipment Directive and ASME XIII. Major companies in the chemical, oil and gas, petrochemical, energy, technical gases, LNG/LPG, pharmaceutical, food and beverage, shipbuilding, heating and air conditioning industries use LESER safety valves for optimal results.


LESER Safety Valves safeguard plants and processes from overpressure incidents. The basis is the LESER product range with nine product groups, 40 types, 1,500 options and over 2,000,000 possible configurations. LESER has constantly adapted its product range to new challenges cropping up every day and is today one of the world’s market leaders for safety valves. In the early project phases, LESER supports customers with technical advice and helps them find the technically best overpressure protection for their objectives. As a result, customers achieve higher efficiency for their plant without delays in later implementation due to technical uncertainties or cost increases. A worldwide network of LESER subsidiaries with their own technical consultants on site guarantees fast and uncomplicated implementation.

LESER Safety Valves for Industrial Applications

Leser safety valve

Safety valves according to API 526 with standardized capacities and dimensions

LESER-Pilotventil-Pilot valve-Safety valve-Sicherheitsventil

High Efficiency

Solutions for high plant efficiency

LESER-Thermal relief valve

Compact Performance

Safety valves with compact dimensions and high connection variety

LESER High Performance Safety valve

High Performance

Safety valves for all industrial applications

LESER Proportioning valve

Modulate Action

Safety valves for low-pressure dynamics


Best Availability

Additional products for higher plant availability

Clean Service-Type 483

Clean Service

Safety valves for food, beverage and pharmaceutical applications

LESER Critical Service PTFE valve

Critical Service

Safety valves with PTFE-lining for corrosive media



Safety valves for heating systems

The Mascot Advantage:

Mascot Systems Private Limited is the Channel Partner for Leser range of Safety & Relief Valves in India and can help you understand the best Valve for your requirement. We also provide after-sales support and service to ensure that your downtime is minimized, leading to optimal capacity utilization and therefore, higher profits.

For your product requirements feel free to contact us