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Emission Requirements and New Ladish Material

Ladish New Product Capability

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API 622 Type Testing of Process Valve Packing

  • The first in a series of Low E valve and packing standards is API 622, which was revised for the third time. This is a test standard for the packing itself. It uses a standardized test fixture (shown below) and eliminates all the variable conditions inherent in each valve. By using a test fixture and a specified set of conditions, a variety of packing sets from multiple manufacturers can be evaluated under the same conditions.
  • The third edition of API 622 restricts leakage of the packing set to a maximum of 100 parts per million volumetric (ppmv), while eliminating the single previously allowed gland bolt adjustment. This edition also adds the requirement of an 1/8-inch packing sample test, which has been problematic in valve type testing, alongside the 1/4-inch packing, which has been used exclusively in all earlier revisions.
  • Currently, API 622 is a performance test. It runs a span of 1,510 mechanical cycles (from open to close) at 600 pounds per square inch gauge (psig) operating pressure over five thermal cycles. Measurements of test gas leakage (methane) are taken periodically throughout the test.
  • During the thermal cycling test, the fixture operates at ambient temperature for 150 cycles. At that point, the temperature is increased to 500 F, running another 150 cycles. This sequence repeats four additional times, and the final stage of the test runs for 10 cycles at ambient temperature.

API 622 Packing Test Apparatus

API 624 – Rising Stem Valve

  • This is a test for the valve itself, including the stem packing. The intention of this test is to measure the low E capability of a valve over an accelerated life cycle. API 624 is a valve-type test meant to evaluate the total performance of the valve itself and not the packing alone.
  • The packing used in an API 624 tested valve should be previously tested to measure up to API 622 requirements.
  • All the variables within a given valve design are being tested in API 624, while the packing has been proven to be, at least theoretically, suitable for use in a low E valve.
  • The test runs a span of 310 mechanical cycles at 600 psig operating pressure over three thermal cycles. All the while, periodic leakage measurements are taken of the test gas, which is specified as methane.
  • During the thermal cycles, the valve will run at ambient temperature for 50 cycles. The temperature is increased to 500 F, and the valve is cycled another 50 times.
  • Finally, the valve is returned to ambient temperature for a run of 10 cycles. Allowable leakage during this test is 100 ppmv at the stem and bonnet seal. No stem seal adjustments are allowed. If at any point the leakage exceeds 100 ppmv, the test is considered a failure.

API 641 – Quarter Turn Test Standard

  • This standard specifies the requirements and acceptance criteria for fugitive emission type testing of quarter-turn valves. The type testing requirements were ORIGINALLY based on elements of EPA Method 21, but that reference has been eliminated.
  • The CURRENT test medium used is methane at 97% minimum purity. The new revision will allow the option for Helium! Emission limit is 100 ppm.
  • Currently a total of 1510 mechanical cycles and 3 thermal cycles
  • NEW! All valve designs shall be classified as Type 1 or 2.
  • Type 1 valve is defined as a valve having a maximum temperature rating that is equal or greater than 260 ° C (500 ° F) and a pressure rating at 260 ° C (500 ° F) equal to or greater than 6.9 barg (100 psig).
  • Type 2 valve is defined as a valve having a maximum temperature rating that is less than 260 ° C (500 ° F) or a pressure rating at 260 ° C (500 ° F) less than 6.9 barg (100 psig).

NOTE: current testing to be completed will confirm if 400C (750F) is the correct high temperature value along with API 622 and 624.

ISO 15848-1 & TA LUFT Testing Summary 

API 608 FLOATING BALL VALVES

  • ISO 15848-1- Certified C01 and C02 Endurance Class
    • Test Valve 2” Class 600 Ball Valve- (Report LETR 1039 Rev. A)
      • Qualifies ½” thru 3” Class 150, 300, and 600
      • Qualifies 4” Class 150 and 300
    • Test Valve 4 Class 600 Ball Valve (Report LETR 1044 Rev A)
      • Qualifies 3” thru 8” Class 150, 300, and 600
      • Qualifies 10” Class 150 and 300
  • TA- Luft Certified
    • Test Valve 2” Class 600 Ball Valve (Report LETR 1043 Rev. A)
      • Qualifies ½” thru 3” Class 150, 300, and 600
      • Qualifies 4” Class 150 and 300

What are the changes in industry & API Standards that will most affect us in 2020-2021?

  • Expansion of Consent Decrees to Small Plants / Natural Gas / LNG: As already seen in the mid-West, regulators are moving from Refining and Large Chemical Plants to small operations including Gas Plants and facilities previously not scrutinized. Low-E will be the buzzword for the coming years.
  • API 641 (Quarter Turn Standard) Moving to Allow Helium as an option for test gas. This could mean another round of testing and customer requirements
  • API 622 (Packing Standard) being amended to reduce the applicable temperature range to 800F (from 1000F). This will increase scrutiny on high temperature valves and require additional testing and documentation from Suppliers.
  • API 624 (Rising Stem Standard) will be effected by the new temperature limits. Valve for use over 800F will not be compliant to API 624.
  • API 607 (Fire Testing): The greatest change in over 10 years will be made in this standard and may result in customers asking for recertification. There is also a trend to testing Gate and Globe Valves to this standard!

Cast Alloy 20 – Ladish Valve Summary

  • Materials:  At present, Ladish stocks Gate, Globe, Check and Ball Valves in both ASTM A351 CN7M as well as the “New” A990 CN3MCu.  We have also supplied A744 CN7M, but this has been either an internal upgrade of the A351 material by PMI and re-annealing when required or by customer specification.
  • Ladish’s opinion is the 2 key factors for A990 yielding a sounder casting are the AOD material requirement and the lower carbon content (as well as phosphorus, sulfur and copper) improves corrosion resistance and reduces the tendency for the casting to have shrinkage porosity and cracks, especially in larger castings.  Ladish has seen a difference in both casting quality and machinability when comparing A990 to A351.
  • It is important to note that within the A990 standard, there are levels of quality that can be dictated with NDE requirements ranging in RT, PT and visual examinations for Class A through D.  Unfortunately, the cost of the A990 is somewhat higher than the CN7M and availability still limited, but we hope this changes over time.  If more Refiners and Chemical Producers specify the A990 CN3MCu, the costs will come down

PART LIST
NO.
PART NAME
MATERIAL
QTY
1
BODY
A744 CN7M
1
3
STEM
B473 N08020
1
4
WEDGE
A744 CN7M
1
7
GLAND
B473 N08020
1
7A
GLAND YOKE
A351-CF8
1
8
HANDWHEEL
A47
1
10
STEM NUT
A276 304
1
11
STEM NUT LOCK NUT
A276 304
1
13
BODY BOLT/STUD
A193 B8M CL.1
14
GLAND EYEBOLT
A276 304/A182 F304
2
15
EYEBOLT NUT
A194 8
2
24
PACKING
GRAPHITE
1 SET
25
BODY GASKET
SPW: A240 N08020 + GRF
1
26
BODY NUT
A194 GR.8M
-
35
YOKE
A744 CN7M
1
38
STEM NUT RETAINER
A276 304
1
39
GREASE FITTING
STAINLESS STEEL
1
40
NAME PLATE
STAINLESS STEEL
1
42
EYEBOLT PIN
A276 304
2
56
SET SCREW
STAINLESS STEEL
1

Alloy 20 Grade Comparison

More than meets the eye…

MaterialRankingWhy
A990 CN3MCu1Casting Consistency, reduced porosity, Improved “Weldability”.  Observation is that this alloy is often preferred with H2SO4 concentrations below 90%.
A744 CN7M2Additional NDE and Required Heat Treatment if welding is performed.  Little Reliability improvement other than formalizing the need for re-annealing after any repair.
A351 CN7M3Good Basic low-cost alloy, but sample NDE testing on a batch basis should be done to verify integrity.

For more information on the standards & materials, please contact us! sales@ladishvalves.com or 281.880.8560. View Ladish materials here.

Once again, Ladish will continue To Mark Progress.

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281.880.8560 or 866-523-4740

7603 Bluff Point Dr. Houston, TX 77086, United States

sales@ladishvalves.com

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