VENT-SAF? Explosion Vents

                                          An explosion can                      result from an ignition of a combustible gas, mist or dust when mixed with                      air during processing, handling or storage operations. A rapid rise in                      pressure occurs in the containing structure, and if it is not of adequate                      strength to withstand the deflagration pressure, extensive damage and                      injury to personnel can occur.
                   

Explosion vents                      are low burst pressure membranes of calculated area fixed over an opening                      on the structure to be protected. In the event of a deflagration the vents                      provide a rapid and unrestricted opening at a predetermined burst pressure                      (Pstat) allowing combustion gases to expand and flow through the open                      vent. The required relief area necessary to protect plant or equipment may                      be determined by using the most current standards of NFPA 68 or VDI 3673.                        
                       
                     The most suitable explosion vent may be selected by matching the                    information in this catalog with the particular operating                    conditions.

The Vent-Saf?                      explosion vents can protect industrial equipment including silos, dust                      collectors, cyclones, conveyers, dryers…and many more.

The Vent-Saf                      Product Line

Types VSP?                      (Vent-Saf Plus ) and VSS? (Vent-Saf Sanitary) domed single section metal                      explosion vents with integral gaskets. The dome is formed to resist                      vacuum.

Type VSE?                      (Vent-Saf Economy) a flat, single section metal explosion vent with                      integral gaskets.

Type EXP/DV? a                      round domed explosion vent of composite construction with integral                      gaskets. The EXP/DV vent has a laser cut stitch pattern in the dome area.                      A fluoropolymer liner covers the slits providing a seal. The vent burst pressure                      is controlled by the arrangement of the stitch pattern.

The Vent-Saf                      vents are available in both round or rectangular styles designed to be                      mounted on the structure to be protected using a Safety                      Frame.

Features and Benefits

Types VSP, VSS AND VSE                    

• Unique, economic and                      patented design.

• Accurate reliable and                      leak tight.

• Enhanced abrasion                      resistance.

• One-piece metal                          construction without slits on the process side avoiding product                      accumulation.

• Optional design for                      aseptic/sanitary applications.

• No fragile PTFE seal that                      may puncture and admit moisture.

• Superior dynamic                      performance due to low mass compared with composite designs.

• Operating pressures up to                          60% of the minimum tagged pressure rating (80% under certain                      conditions).

• Thermal insulation                          available to permit use in operating temperatures to 2000°F/1093°C, to                      reduce heat loss or prevent condensation.

• Supplied with integral                      gaskets ready for installation.

• Fail-safe design, if                      damaged it will provide a relief opening below its rated pressure.

Specification Data                      and Ordering Checklist
                   The items to consider in                      selecting and ordering an explosion vent. For an Application Data Sheet                      listing required information contact BS&B.

• Product name                        (example:VSP).

• Size.

• Positive burst pressure                        (Pstat) at coincident temperature.

• Normal operating pressure                        and temperature.

• Maximum operating                        pressure and temperature.

• Maximum vacuum pressure.

• Process media                        compatibility with materials of vent.

• Pressure cycling                        conditions.

• Frames (bolted, welded);                        panel bolt pattern, BS&B standard or special, please specify.

• Optional insulation                        design.

• Optional sanitary/aseptic                        design

• Optional magnetic burst                        sensor (specify if armored cable or factory installation of switch on                        frame is required).

• Optional full gaskets.

• Other special                        requirements.

Types VSP & VSS

Burst Pressure                      (pstat)Burst pressures are                      available from 0.3 psig (0.021 barg) to 5 psig (0.35 barg) depending on                      vent size and configuration.
                     
                     Vacuum                        ServiceThe VSP and VSS vents with                      their domed constructions are designed to resist high vacuum under cycling                      conditions without the need for vacuum support bars attached to the inner                      safety Frame. The vacuum rating of a vent is dependent on the vent’s burst                      pressure, consult BS&B Safety Systems, Inc or BS&B Safety Systems,                      Ltd.
                     
                     Service                        CapabilitiesThe VSP vent has been                      tested to over 1 million pressure cycles from vacuum to light positive                      pressure while retaining its burst accuracy. The VSP vent exhibits                      superior performance compared to conventional composite vents that fatigue                      after less than 40,000 pressure cycles under equivalent test                      conditions.The type VSS vent is of                      similar construction to the type VSP vent and is suitable for static or                    cyclic vacuum service conditions only.

Type VSE

Burst Pressure                      (pstat)Burst pressure is available                      from 0.25 psig (0.017 barg) to 5 psig (0.35 barg) depending on vent size.                      The VSE vent will burst at the same pressure in both directions.
                     
                     Vacuum                        ServiceThe VSE must be installed                      in a Safety Frame with vacuum support bars in order to withstand vacuum or                      back-pressure.
                     
                     Service                        CapabilitiesThe VSE is designed for                      atmospheric, or static pressure service conditions.

Round VSE VENTS. There are                      two standard designs providing a one petal or four petal shape relief                      openings. The four-petal design offers high burst                      pressure.

Types VSP, VSS & VSE

Operating Pressure                      The VSP, VSS and                        VSE vents are suitable for positive pressures up to 60% of the minimum                        burst pressure. However , under certain conditions up to 80% of the                        minimum burst pressure is possible. Consult BS&B Safety Systems,                      Inc.

Vent OperationThe perimeter of                        the rectangular or square vents are laser cut on three sides in a stitch                        pattern. The fourth side acts as a hinge, and retains the central section,                        controlling fragmentation upon opening of the vent The laser cut slits in                        the vent are covered by integral gaskets or sealing material to achieve a                        leak tight sealed construction.

Materials of                      ConstructionThe VSP, VSE and                        VSS explosion vents in 316SS* standard material are available with a                        variety of gasket and seal materials depending on the                        application.
                     
                                                                               

For economy half                        silicone sponge gaskets are provided as standard which cover half the                        flange to the bolt holes. Full gaskets may be supplied on request.                        Alternative gasket materials including Neoprene and Solid Viton? are also                        available.

*Vents are                        available in alternative materials.

‘Silicone sponge                        component acts as a gasket/seal and is fitted to both sides of the                        vent.
                       Viton? is a                        registered trademark of Du Pont Dow Elastomers LLC

Burst                      Tolerance

An alternative                        tolerance of +/-0.25 % may be offered if required by the customer, contact                        us. The tag is affixed to the discharge side of the vent will be marked                        with a minimum-maximum burst pressure range.

Rectangular and Round                        Explosion Vent Dimensions

The dimensions                        and relief areas of VSP and VSE vents in either rectangular or round                        designs are given in Tables 1 and 2. Contact BS&B Safety Systems, Inc.                        or BS&B Safety Systems, Ltd. for non-standard sizes.

Safety                        Frames

Rectangular vents                        can be mounted in lightweight angle profile Safety Frames. Round vents can                        be installed between standard weld neck flanges in accordance with ANSI                        150 or DIN PN10 or in lightweight angle profile frames. Safety frames are                        available in 304SS or carbon steel.

The frames are                        designed to either bolt or weld on to the equipment to be protected. If                        frames are manufactured by the user, details of bolt sizes, spacing and                        dimensions must be given to BS&B Safety Systems, Inc. prior to vent                        manufacture to ensure correct vent performance.

Operating                        Temperature

The standard                        explosion vent may be used in temperatures –40°F to 300°F (-40°C to                        150°C), the sanitary/aseptic design –80°F to 450°F (-62°C to 232°C) and                        with solid silicone gaskets the RTV (High Temperature) seal –80°F to 500°F                        (-62°C to 260°C). Alternative vent construction permits higher                        temperatures.

Sanitary/Aseptic                        Applications

These explosion                        vents of single section stainless steel construction with smooth internal                        surface finish are free of cavities. Solid White silicone gaskets are                        supplied fitted to the vent flange area and FDA approved RTV sealing                        material applied to the vent perimeter to achieve a sanitary/aseptic                        construction.

Thermal                        Insulation

Thermally                        insulated vents using either urethane or ceramic material may be offered                        to prevent heat loss or condensation on the vent. Insulation will also                        permit their use in high temperature service up to 2000°F (1093°C). The                        insulation is integral to the panel construction, requiring no additional                        field installation. The type and thickness of the insulation material will                        be selected to suit the operating temperature requirements. The additional                        insulation is taken into consideration when the burst pressure is                        determined. An optional stainless steel weather cover is available to                        provide added protection of the insulation against rain, ice or                        debris.

Burst Sensor

The MBS? Type                        magnetic sensor is available to provide immediate warning upon bursting of                        the explosion vent. A magnetic activator is fitted to the vent and a                        proximity switch attached to the safety frame. Warning of a burst vent is                        given when the current flowing through the sensor is disrupted giving an                        open circuit signal. The sensor is suitable for use in hazardous areas                        provided a suitable power level or Zener barrier is used to meet                        intrinsically safe requirements. An armored style sensor is also                        available.

RECTANGULAR                        VSP, VSS AND VSE VENT DIMENSIONS

ROUND VSP AND VSE VENT                        DIMENSIONS

Type EXP/DV

Type EXP/DV Vent                      is a round domed vent of composite construction laser cut in a stitch                      pattern in the done area. An FEP/PTFE liner covers the slits providing a                      seal. The vent burst pressure is controlled by the arrangement of the                      stitch pattern.

Burst Pressure                        (pstat)From 1 psig (0.07                      barg) and above depending on size.Sizes: 6" (150                      mm) to 48" ( 1200 mm) relief diameter.Vacuum                        ServiceThe EXP/DV vent                      is fitted with a vacuum support to resist high vacuum.

Service                        CapabilitiesThe type EXP/DV                      vent exhibits good performance under pressure cycling conditions from                      vacuum to light positive pressure.

Burst                        ToleranceThe Burst                      Tolerance is +/- 0.5 psig (0.034 barg) of the nominal burst pressure. A                      tag is fixed to the discharge side of the vent and marked with the burst                      pressure range. Example: A vent with a nominal burst pressure of 3 psig                      (0.21 barg) will be tagged minimum 2.5 psig ( 0.17 barg) - maximum 3.5                      psig (0.24 barg).

MaterialsThe top or burst                      control section and the vacuum support are 316SS. The seat is fluoropolymer.                      Other top section and seal materials are available.

Operating                        PressureThe EXP/DV vents                      are suitable for positive operating pressures up to 80% of the minimum                      burst pressure. Example: A vent with a nominal burst pressure of 2.5 psig                      (0.17 barg) is suitable for operating pressure up to 2 psig ( 0.138                      barg).

InstallationThe EXP/DV vent                      can be installed between standard weldneck flanges in accordance with DIN                      PN 10, ANSI 150 or directly on to the structure to be protected. The vent                      must always be installed with a hold-down ring on the outer side to ensure                      proper performance. The vents are supplied with gaskets ready for                      installation.

Operating                        Temperature-40°F (-40°C) to                      500°F (260°C)Thermally                      insulated vents using ceramic fiber material may be offered to prevent                      heat loss or condensation on the vent or to permit their use in high                      temperature service up to 2000°F (1093°C).

Type LCV
                     The EXP/LCV vent                      is a rectangular flat vent of composite construction laser cut in a stitch                    pattern around the vent’s perimeter.

Vacuum                    Service
                   The LCV vent is                    fitted with a support to resist vacuum.

Burst Pressure                      (pstat)
                     0.5 psig (0.035                      barg) to 5 psig (0.35 barg), depending on size, and in the same sizes as                      types VSP and VSE vents.

Service                      Capabilities
                     The type EXP/LCV                      vent is designed for static or light pressure cycling duty.

Burst                    Tolerance
                   The Burst                      Tolerance is +/-0.25 psig (0.017 barg) of the nominal burst pressure. Tags                    are marked with a min/max burst range.

Materials
                     The top section                      is 316SS with a fluoropolymer seal. Other top section materials are                    available.

Operating                      Pressure
                     The vents are                      suitable for operating pressures up to 60% of the minimum burst                    range.

Installation
                   The type EXP/LCV                      vent is supplied with gaskets ready for installing in Safety                    Frames
                   
                   For technical                      assistance on any explosion vent contact BS&B Safety Systems,                      Inc.
                     
                   fluoropolymer is                    generally used other appropriate fluorocarbons may be supplied.