I've done several transformer yards and usually use clean crush 'Fire Quenching Stone' to the following (from my Project Notes)
FIRE QUENCHING STONE (ALBARRIE CONTAINMENT SYSTEM)
CLEAN, WASHED, ANGULAR CRUSHER RUN LIMESTONE CONSISTING OF HARD DURABLE PARTICLES FREE FROM SILT, CLAY AND SILT LUMPS, FRIABLE MATERIALS, CEMENTATION, SOLUBLE MATERIALS, FROZEN MATERIALS AND ORGANIC MATTER. VOID RATIO 45% MIN
FILL SHALL CONFORM TO:
SIEVE SIZE (ASTM) PERCENT PASSING
3 100
1-1/2 0-2
3/4 0-1
FIRE QUENCHING STONE (ALBARRIE CONTAINMENT SYSTEM)
CLEAN, WASHED, ANGULAR CRUSHER RUN LIMESTONE CONSISTING OF HARD DURABLE PARTICLES FREE FROM SILT, CLAY AND SILT LUMPS, FRIABLE MATERIALS, CEMENTATION, SOLUBLE MATERIALS, FROZEN MATERIALS AND ORGANIC MATTER. VOID RATIO 45% MIN
FILL SHALL CONFORM TO:
SIEVE SIZE (ASTM) PERCENT PASSING
75 100
37.5 0-2
19 0-1
FIRE QUENCHING STONE (ALBARRIE CONTAINMENT SYSTEM)
CLEAN, WASHED, ANGULAR CRUSHER RUN LIMESTONE CONSISTING OF HARD DURABLE PARTICLES FREE FROM SILT, CLAY AND SILT LUMPS, FRIABLE MATERIALS, CEMENTATION, SOLUBLE MATERIALS, FROZEN MATERIALS AND ORGANIC MATTER. VOID RATIO 45% MIN
FILL SHALL CONFORM TO:
SIEVE SIZE (CAN METRIC) PERCENT PASSING
75000 100
40000 0-2
20000 0-1
This is used with their product Sorbweb... a material that gels when exposed to transformer oil. There is a 'window' in the entrapment basin that allows rainwater to pass, but chemically seals to keep oil from passing... It's an excellent product and have used it about a dozen times.
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik