intrinsic safe sov

Which sov did you want to compromise?

Check with this guy, he knows"

by-passing transformer differential relay

You'd make a great team!

Dear lynlynch

sov mens Solenoid valve......what chart you has given its a bullshit.

even i understood what is sov.

shut down valve is not abbreviated as SOV. it is XV .....as per ISA symbol.

Dear guest

SOV should connceted to IS barrier or not ...It depends on where SOV is installed.

if the place is not instrinsically safe then......you have to conncet Optical barrier/Galvanic barrier. which is a isolation between a safe zone and unsafe zone.

Please post the exact EEx symbol on the SOV for further guidance, together with its certification number <subscribes to discussion>.

The only way to use an IS valve is to have it connected to a source that protects the loop based on the entity values of the device. some control systems offered IS outputs that would need to provide the limiting parameters (current, voltage, power) to the field device. Thus meeting the criteria of Intrinisic Safety.

If you have an system that is already Intrinisically Safe. You would need to look at the barrier / isolator that is in place and then match the Solenoid valve that would would best meet the limited values ie be equal to and not greater than that of the Isolator/barrier.

If it is replaced with a non IS valve then the wiring to the device must meet the electrical classification requirments for the installation. ie explosion proof enclosures, seals, rigid conduit all may be part of the installation.

IS wiring can be just instrument rated cable in tray or some method of transport to the device and a simple gland to enter into the device as the IS protection is for the wiring, field device and safe area protection.

Hope this helps... also information on IS practices can be found at www.rstahl.com...

http://en.wikipedia.org/wiki/Intrinsic_safety

There is no such thing as an IS sov, as IS is a method of circuit protection. Without knowing the EEx technique to be employed, it is not possible to advise further. _{<unsubscribes>}

There are listed IS SOV's, they carry a listing with an approval agency that provides the entity parameters in a control drawing maintained by the manufacturer. Also as you indicate it is a concept (method) of protection that the valve alone will not provide the protection in the field. There must be other devices referred to as an "approved apparatus" that provides the interface between the hazardous area and safe area. This could be a single device or a type of IO or a control system that carries an apporval to protect to a certain level that is matched with the end device parameters.

This not only protects the device from reaching a dangerous potential but also protects the field wiring in the case of a fault and provides a means of preventing problems in the safe area from reaching the hazardous area... below is a link to an IS solenoid valve from Asco...

http://www.lesman.com/unleashd/catalog/valves/valves_isseries.html

Can a intrinsic safe sov be connected directly without barrier or can it be replaced with non IS sov ??

It is a concept ie method of protection that requires all of the componets from the final device through the wiring from a protection device barrier or isolator that provides the limitation of current, voltage, power and limits the additional capacitance and inductance are to be considered together.

First question is the loop proven as IS? if yes then replacing the IS SOV with a non IS solenoid makes the installation unsafe if the area was deemed hazardous by the electrical classification. if you change out the wiring methods ie exp conduit and addition of seals the installation can then be inspected by the AHJ to deterimine if the installation (protection of the wiring and ingress of gasses) is correct.

Second if you replace only a Non IS SOV with an IS SOV that does not make the loop intriniscally safe unless a matched Isolator or Barrier in placed in the Loop to provide the protection to the hazardous section of the wiring and final device.