The America Petroleum Institute screen labeling practice (API RP 13E) has been replaced with API RP 13C. API is a physical testing and labeling procedure for shale shaker screens. The new API RP 13C labeling practice provides a standard for comparing one manufacturer’s shale shaker screen separation against another.
To be API RP 13C compliant, a shale shaker screen must be tested and labeled in accordance with this recommended practice. Internationally, API RP 13C is known as ISO 13501. The API designation for a shale shaker screen is the API-defined range of sizes into which the D100 value falls. The D100 value represents the diameter of the coarsest particle (in microns) which will pass through the shale shaker screen during a dry laboratory test. This is a single number, not a range of sizes. Some of the coarser size classes span quite a large range of D100 values.
However, customers are advised to continue using the shale shaker 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 of shale shaker screen to use.
The previous test procedure for shale shaker screens (API RP 13E) measured the distribution of the screen holes as measured by light, not solids. Subsequently, the shale shaker screens were labeled using the D50, D16 and D84 separation curve.
The current, new test procedure (API RP 13C) measures the coarsest particle which passes through the shale shaker screen, using a much more accurate and repeatable test method. The shale shaker screens are now labeled using the D100 size criteria.
Since the two standards measure the shale shaker screens using two different test procedures and the classifying number also changes from D50 to D100, the API RP 13C values will be different from the API RP 13E values for the same shale shaker screen.
We intend to remain 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 shale shaker screen designation.