Total sediment in residual fuel: TSP, TSA and TSE
The three ISO 10307 sediment measurements, the 0.10 percent TSP conformance limit, the 10 g filtration rule, and why TSA was demoted in 2024.
Total sediment is the measure of a residual fuel’s tendency to drop asphaltenes out of suspension, and ISO 8217:2024 records it three ways distinguished by the ageing applied before filtration. TSE, existent total sediment, is the sediment present at the time of test by hot filtration under ISO 10307-1. TSP, potential total sediment, is measured after ageing for 24 hours at 100 degrees C under ISO 10307-2 Procedure A. TSA, accelerated total sediment, is measured after dilution with a paraffinic solvent then one hour at 100 degrees C under Procedure B.
Annex H explains what each represents: TSP is representative of the fuel’s resistance to thermal stress, while TSA represents its tolerance for retaining asphaltenes in suspension when commingling with a paraffinic fuel under limited thermal stress.
TSP at a maximum of 0.10 percent by mass is the conformance measure and the reference method in a dispute across all three residual tables. For Tables 2 and 3 only TSP may be used to judge conformance; for Table 4 either TSA or TSP may be used. A footnote adds that the limit applies to a 10 g test specimen and that failure to complete filtration of 10 g within 25 minutes means the fuel does not meet the specification. TSA was demoted in the 2024 edition because the relationship it relied on broke below roughly 200 mm2/s. The full article will cover each method, the sampling that supports it, and how a sediment result is used in a bunker quality claim.