Fire safe valve


۱- آیا برای فایر سیف ولوها، باید فقط سافت سیت استفاده کرد؟از چه جنسی باشد؟
۲- آیا سیت در فایر سیف ولوها میتواند متال باشد؟
۳- برای باترفلاهای هم فایر سیف تعریف میشه؟ سیلینگ در اینجا چه طوری پیاده سازی میشه؟
۴- برای کنترل ولوها هم فایر سیف تعریف میشه؟ در اینجا سیلینگ چطوری پیاده سازی میشه؟

1- بله چون اب بندی بهتر دارد. مثلا graphite می تواند استفاده شود.
2- خیر
3- بله اب بندی دیسک با سیت انجام می گردد.
4- برای globe valve ها تعریف نمی شود چون ذات شیر کلاس نشتی بالایی ایجاد نمی کند.

API 607 provides fire test criteria for quarter-turn valves and other valves with nonmetallic seating under pressure, whereas API 6FA provides the fire testing requirements for API 6A and API 6D valves. API 6FA is applicable for metal seated valves.

  • Fire Safe by Design: A “fire safe by design” valve is designed to make the valve fire safe. However, the valve hasn’t been tested.
    • Fire Safe Tested: A “fire safe tested” valve could have been tested. However, the valve has not been approved by a governing third party.
    • Fire Safe Approved and Certified: The term “fire safe approved and certified” for valves signifies that they have been tested, approved, and certified by a governing third party following the guidelines mentioned in common standards like API 607, API 6FA, ISO 10497, etc.

Principle of Fire Testing of Valves
The idea behind the fire tests is that any fire-safe valve under pressurized conditions must operate after being burnt at a specified high temperature for a specified period and leakage after burning should be within specified limits. The usual principle of fire testing of valves or fire-safe valve testing is as follows:
The water-filled pressurized closed valve is fully enveloped uniformly in high-temperature flames of around 750 °C to 1000 °C for a period of 30 minutes. When the valve is completely enveloped in fire exposing the seat and sealing areas to burn temperature, the heat intensity is monitored with thermocouples and calorimeter cubes. During this period, the external and internal leakage past the valve is measured. This leakage should be within acceptable limits. Also, once the valve is cooled after the fire test, the pressure-containing capability of the same valve seats, shell, and seals are tested.

  * The stem and bore are usually kept in the horizontal position. Check valves are tested in their normal operating position.

  * The temperature is measured using two thermocouples. One is located 25 mm below the valve under test and the other 25 mm from the upper stem packing box on the horizontal centreline.

  * The piping to valve end connections for joint leakage is not part of valve fire testing