• API RP 13C Compliance Definitions, Clarity, and FAQs

    BRANDT™ Screens Comply with API RP 13C

    The America Petroleum Institute screen labeling practice, API RP 13E, has been superseded and merged with API RP 13C. NOV has provided this document as a clarification during the introduction of this new practice. Previously, API RP 13E used light to measure the distribution of hole sizes and then calculated values for D16, D50 and D84.

    • Now, API RP 13C uses particles to measure the coarsest particle that passes through the screen, resulting in a measured value of D100.
    • Historically API RP 13E’s D50 was considered the primary cut-point of the screen. Currently, API RP 13C uses D100 to compare two different screens.
    • Separation curves show that the D100 value is always coarser than the D50 value. 

    NOV views the change from API RP 13E to API RP 13C as a positive step, because of the move from a light basis to a particle separation basis. Since the two standards measure the screens using two completely different test procedures and the classifying number also changes from D50 to D100, the API RP 13C values will be different than API RP 13E values for the same screen.

    API RP 13C - An Explanation & FAQ's 

    FAQs

    1. What is the D100 and how is it related to the API screen designation?

    • The D100 value represents the diameter of the coarsest particle (in microns) which will pass through the screen during a dry laboratory test and is a single number, not a range of sizes.
    • The API screen designation for a screen is the API-defined range of sizes into which the D100 value falls. Some of the coarser size classes span quite a large range of D100 values.


    2. What does/doesn’t the D100 tell us?

    • The D100 value is the finest particle diameter at which the screen no longer sends 100% of the particles to the discard stream. This is also the coarsest particle that will pass through the screen.
    • The D50 value is the particle size at which the screen sends 50% of the particles to the “overs” (discard), while the remaining 50% report to the “unders” (undersized stream) and the D100 should not be compared in any way. The D50 was interpreted as the micron size where a screen makesa 50/50 split. 
    • The API RP 13C D100 is a very specific value determined from a carefully-controlled laboratory procedure so that any laboratory should measure the same value for any given screen cloth.


    3. Will a screen with a D100 of 110 microns remove solids finer than 110 microns?

    • Yes, more than half of the particles that are coarser than D50 and finer than D100 will report to the overs. A significant portion of the particles finer than D50 will also report to the unders. (By definition, every particle classified in the D100 size or coarser will report to the overs as expected.)


    4. Have any of the BRANDT screen mesh combinations changed?

    • Yes, however only a few of the screen mesh combinations required a change in order to provide a screen in each API Screen designation.
     

    5. Why is there such a great variance between the old and new screen labeling values?

    • The biggest variation is due to the shift from the D50 value to the D100 value.
    • The previous test procedure for screens, API RP 13E, measured the distribution of the screen holes as measured by light, not solids. Subsequently, the screens were labeled using the D50, D16 and D84 separation curve.
    • The current test procedure, API RP 13C, measures the coarsest particle which passes through the screen, using a much more accurate and repeatable test method. The screens are now labeled using the D100 size criteria.



    6. Should I use the old screen number or the new API screen designation when ordering replacement screens?

    • BRANDT intends to remain completely flexible and will accept orders according to the system that customers prefer. Orders may be placed using either the old nomenclature or the new API screen designation.
     

    7. Should I screen with a finer screen now if whait I used to call a 200-mesh screen is now labeled an API 120?

    • Customers are advised to continue using the screens that work best for their applications, regardless of the new API screen designation. The sand content found in the mud report remains the best indicator of what type screen to use. The new testing procedure reports a different value and its primary intent is to provide a standard measuring system for comparing screens among competing manufacturers.
    • BRANDT advises to “screen with a purpose”. The mud report will dictate what type of screen is required. With a weighted mud, the mud should be screened fine enough to produce just a trace of sand. If the mud report is showing a sand content of .25% or more, the advice is: screen finer. With an unweighted mud, the mud should be screened as fine as possible (with consideration to practical screen life), while maintaining the prescribed mud weight.
     

    8. Why does BRANDT choose to use both original screen nomenclature, as well as the new API RP 13C screen designation?

    • It is expected that customers will refer to both the original and the new nomenclature for an indefinite period. BRANDT will continue to use its original nomenclature and provide information regarding correlating API RP 13C screen designations to allow customers to choose what works best for them.
     

    9. What is the practical value of the new API RP 13C screen labeling practice to the end user?

    • The new API RP 13C labeling practice provides an excellent standard and benchmark for comparing one screen manufacturer’s screen separation against another. The closer the D100 values, even within the same size class, the better the comparison will be.
    • BRANDT will work with customers to ensure that screen comparison tests are performed in a fair manner to both the competition and to BRANDT, allowing the development of a balanced test plan, including a double-blind particle size analysis protocol, whenever a screen comparison is to be conducted.


    From flowline to disposal, NOV has the solutions to your separation and waste management needs. BRANDT is a subsidiary of National Oilwell Varco, the industry’s technological leader.

    Description

    BRANDT™ Screens Comply with API RP 13C

    The America Petroleum Institute screen labeling practice, API RP 13E, has been superseded and merged with API RP 13C. NOV has provided this document as a clarification during the introduction of this new practice. Previously, API RP 13E used light to measure the distribution of hole sizes and then calculated values for D16, D50 and D84. 

    • Now, API RP 13C uses particles to measure the coarsest particle that passes through the screen, resulting in a measured value of D100.
    • Historically API RP 13E’s D50 was considered the primary cut-point of the screen. Currently, API RP 13C uses D100 to compare two different screens.
    • Separation curves show that the D100 value is always coarser than the D50 value. 

    NOV views the change from API RP 13E to API RP 13C as a positive step, because of the move from a light basis to a particle separation basis. Since the two standards measure the screens using two completely different test procedures and the classifying number also changes from D50 to D100, the API RP 13C values will be different than API RP 13E values for the same screen.

    API RP 13C - An Explanation & FAQ's 

    FAQs

    1. What is the D100 and how is it related to the API screen designation?

    • The D100 value represents the diameter of the coarsest particle (in microns) which will pass through the screen during a dry laboratory test and is a single number, not a range of sizes.
    • The API screen designation for a screen is the API-defined range of sizes into which the D100 value falls. Some of the coarser size classes span quite a large range of D100 values.


    2. What does/doesn’t the D100 tell us?

    • The D100 value is the finest particle diameter at which the screen no longer sends 100% of the particles to the discard stream. This is also the coarsest particle that will pass through the screen.
    • The D50 value is the particle size at which the screen sends 50% of the particles to the “overs” (discard), while the remaining 50% report to the “unders” (undersized stream) and the D100 should not be compared in any way. The D50 was interpreted as the micron size where a screen makesa 50/50 split. 
    • The API RP 13C D100 is a very specific value determined from a carefully-controlled laboratory procedure so that any laboratory should measure the same value for any given screen cloth.


    3. Will a screen with a D100 of 110 microns remove solids finer than 110 microns?

    • Yes, more than half of the particles that are coarser than D50 and finer than D100 will report to the overs. A significant portion of the particles finer than D50 will also report to the unders. (By definition, every particle classified in the D100 size or coarser will report to the overs as expected.)


    4. Have any of the BRANDT screen mesh combinations changed?

    • Yes, however only a few of the screen mesh combinations required a change in order to provide a screen in each API Screen designation.
     

    5. Why is there such a great variance between the old and new screen labeling values?

    • The biggest variation is due to the shift from the D50 value to the D100 value.
    • The previous test procedure for screens, API RP 13E, measured the distribution of the screen holes as measured by light, not solids. Subsequently, the screens were labeled using the D50, D16 and D84 separation curve.
    • The current test procedure, API RP 13C, measures the coarsest particle which passes through the screen, using a much more accurate and repeatable test method. The screens are now labeled using the D100 size criteria.



    6. Should I use the old screen number or the new API screen designation when ordering replacement screens?

    • BRANDT intends to remain completely flexible and will accept orders according to the system that customers prefer. Orders may be placed using either the old nomenclature or the new API screen designation.
     

    7. Should I screen with a finer screen now if whait I used to call a 200-mesh screen is now labeled an API 120?

    • Customers are advised to continue using the screens that work best for their applications, regardless of the new API screen designation. The sand content found in the mud report remains the best indicator of what type screen to use. The new testing procedure reports a different value and its primary intent is to provide a standard measuring system for comparing screens among competing manufacturers.
    • BRANDT advises to “screen with a purpose”. The mud report will dictate what type of screen is required. With a weighted mud, the mud should be screened fine enough to produce just a trace of sand. If the mud report is showing a sand content of .25% or more, the advice is: screen finer. With an unweighted mud, the mud should be screened as fine as possible (with consideration to practical screen life), while maintaining the prescribed mud weight.
     

    8. Why does BRANDT choose to use both original screen nomenclature, as well as the new API RP 13C screen designation?

    • It is expected that customers will refer to both the original and the new nomenclature for an indefinite period. BRANDT will continue to use its original nomenclature and provide information regarding correlating API RP 13C screen designations to allow customers to choose what works best for them.
     

    9. What is the practical value of the new API RP 13C screen labeling practice to the end user?

    • The new API RP 13C labeling practice provides an excellent standard and benchmark for comparing one screen manufacturer’s screen separation against another. The closer the D100 values, even within the same size class, the better the comparison will be.
    • BRANDT will work with customers to ensure that screen comparison tests are performed in a fair manner to both the competition and to BRANDT, allowing the development of a balanced test plan, including a double-blind particle size analysis protocol, whenever a screen comparison is to be conducted.


    From flowline to disposal, NOV has the solutions to your separation and waste management needs. BRANDT is a subsidiary of National Oilwell Varco, the industry’s technological leader.