05202018Sun
Last updateFri, 18 May 2018 4pm

i

The Past, Present and Future of Fire Testing

The Past, Present and Future of Fire Testing

Because so many of the applications wher...

Advancements in Blue Laser Scanning

Advancements in Blue Laser Scanning

As the industrial world continues to exp...

Cavitation in Globe Valves—and Proposed Solutions

Cavitation in Globe Valves—and Proposed Solutions

Straight pattern globe valves are widely...

The VMA Knowledge Forum, Part Two: The Human Factor

The VMA Knowledge Forum, Part Two: The Human Factor

Finding and retaining the right talent i...

SubscribeSPR18

FREE SUBSCRIPTION*

• Print magazine
Digital magazine
• VALVE eNews
Read the latest issue

*to qualified valve professionals in the U.S./Canada

The Weekly Report

New Products

  • ja-news-2
  • ja-news-3

Industry Headlines

Emerson Agrees to Buy Aventics

Friday, 18 May 2018  |  Chris Guy

Emerson has agreed on terms to acquire Aventics from Triton for a cash purchase price of $620 million. Aventics deals in smart pneumatics technologies...

Readmore

Loading...
Advertisement
i

Industry Headlines

Emerson Agrees to Buy Aventics

2 DAYS AGO

Emerson has agreed on terms to acquire Aventics from Triton for a cash purchase price of $620 million. Aventics deals in smart pneumatics technologies that power machine and factory automation applications. Aventics significantly expands Emerson’s reach in a growing $13 billion market.

With cen...

Readmore

Conval Names Brian White Refining & Chemical Industry Manager

3 DAYS AGO

Conval has appointed Brian E. White as refining & chemical industry manager serving the petrochemical industry in the Gulf states and elsewhere as opportunities and needs arise.

Based in Houston, White has over 20 years of experience selling instrumentation and capital equipment to the oil & ga...

Readmore

Outside of U.S., Natural Gas Outlook Diminishing

3 DAYS AGO

The mood in the natural gas industry, at least outside the U.S., is not as optimistic as it once was. According to the International Energy Agency (IEA), demand has slowed considerably for most of the period since 2011, from an average of 2.8% per year between 2000 and 2010, to 1.4% per year from 2011...

Readmore

ExxonMobil, BASF Form Gas Treating Alliance

3 DAYS AGO

ExxonMobil Catalysts and Licensing LLC and BASF Corporation have signed an alliance agreement to jointly develop new gas treating solvents and process technologies for use in natural gas processing and petroleum refining. Under this new agreement , BASF will market and license technologies developed f...

Readmore

Leading Economic Indicators Up 0.4% in April

2 DAYS AGO

The Conference Board Leading Economic Index (LEI) for the U.S. increased 0.4% in April to 109.4, following a 0.4% increase in March, and a 0.7% increase in February.

April’s increase and continued uptrend in the U.S. LEI suggest solid growth should continue in the second half of 2018. How...

Readmore

U.S. Factory Output Rose in April

3 DAYS AGO

Industrial production rose 0.7% in April for its third consecutive monthly increase. The rates of change for industrial production for previous months were revised downward, on net; for the first quarter, output is now reported to have advanced 2.3% at an annual rate.

Manufacturing output moved up 0.5...

Readmore

Advertisement

Safety-Relief Valve FAQ

Our company routinely receives inquiries from end users about their safety-relief valves.

Here are some of the most frequently asked questions...


Q:  What is the proper way to install a safety or safety-relief valve?

A: Safety and safety-relief valves should be installed vertically with the drain holes open or piped to a convenient location. All piping must be fully supported.

 

Q:  How often should I test/ inspect my valve?

A: Maintenance should be performed on a regular basis. An initial inspection interval of no longer than 12 months is recommended. The user must establish an appropriate inspection interval depending on the service conditions, the condition of the valve and the level of performance desired.

The ASME Boiler and Pressure Vessel Code does not require nor address testing installed valves. The only thing the code states are design and installation requirements, such as some valves must have a lifting lever. For instance for Section VIII:

“Each pressure relief valve on air, water over 140° F, or steam service shall have a substantial lifting device which when activated will release the seating force on the disk when the pressure relief valve is subjected to a pressure of at least 75% of the set pressure of the valve.”

Q: What mounting orientation should be used to install a safety valve?

A: Installing a safety valve in any position other than with the spindle vertical and upright may adversely affect performance and lifetime.

Q:  Why is there a hole in the valve body?

A: This drain hole is required on some models by the ASME Boiler and Pressure Vessel Code. It is intended to prevent any condensate from accumulating in the body that may freeze or corrode internal valve parts and prevent the valve from opening. The drain hole should be piped away to safely dispose of any discharge or condensate.

Q: Which end should be connected for vacuum valves?

A: This is often a confusing topic. The correct installation often looks backwards from what appears to be correct. A paper instruction tag illustrating the proper connection is attached to each valve. Vacuum valves should have the NPT threads that are cast integral to the body attached to the vacuum source. See the assembly drawing for additional clarification.

Q:  What set pressure should the valve be set to open?

A: Typically, the valve should be nameplate set to open at the MAWP (Maximum Allowable Working Pressure) of the vessel the valve is intended to protect. There is a tolerance to actual set pressure, which means a valve set at 100 psig nameplate may open slightly above or below 100 psig. Consult the current ASME Boiler and Pressure Vessel Code for tolerance classes and special situations when the set pressure may be different than the MAWP.

Q:  Why is my valve leaking?

A: It is normal for spring-operated safety valves to exhibit leakage or simmer/warn, as the system operating pressure approaches the nameplate set pressure, typically in the 80%-90% range of nameplate set pressure. The ASME Boiler and Pressure Vessel Code does not require a specific seat tightness requirement. A certain level of leakage is allowed per manufacturers’ literature and API-527 Seat Tightness Performance Standards, both of which can be found in the Technical Reference Catalog and in the Data Supplement, summarized as follows:

  • Factory Standard Seat Tightness Performance: No visible (no audible for air service) leakage for 15 seconds (30 seconds for liquid or Section IV steam service) at 20% below nameplate set, or 5 psig below nameplate set, whichever is greater. EXCEPTION: Section IV steam service is checked at 12 psig.
  • API-527 Standard Seat Tightness Performance: A Functional Test Report (FTR) is automatically provided for valves ordered to API-527. See API 527 for complete details.

At very low set pressures, the ratio of the downward spring force as compared to the upward pressure force is very small. In these cases it may be impossible to achieve seat tightness.

Use soft seats for superior seat tightness, assuming the application falls within the soft seat temperature limitations. Although soft seats will typically provide a higher degree of seat tightness than metal seats, Factory Standard does not ensure bubble-tight seats, regardless of seat material.

  • Latest Post

  • Popular

  • Links

  • Events

BUYERS GUIDE 300x220

Looking for a career in the Valve Industry?

ValveCareers Horiz

To learn more, watch the videos below or visit ValveCareers.com a special initiative of the Valve Manufacturers Association