Text Box: Table 1	Requirements for fly ash given in BS EN 450 (1995) and BS 3892, Part 1 (1997)
Property	BS EN 450	BS 3892, Part 1
Fineness, max. (% retained on 45mm)	40.0	12.0
Fineness variation	± 10.0 on mean value.	--
Loss on Ignition, (%)	5.0 (7.0 on national basis)
auto-controlled	7.0 max
Particle density (kg/m3)	± 150 on mean value.	³ 2000
Chemical Composition:		
SO3, max. (%)	3.0	2.0
CaO - Free, max. (%)	1.0 or 2.5(i)	--
CaO - Total, max. (%)	10 (sub-bituminous ashes)	10
Chloride, max. (%)	0.10	0.10
Moisture content, max. (%)	(ii)	0.5
Water requirement, max. (%)	--	95
Activity index, min. (%) (iii)	75 (28 days)
85 (90 days)	80 (28 days)
Soundness (mm)	10(i)	10
(i)	Soundness test required only if free CaO exceeds 1%.
(ii)	Fly ash to be stored and transported dry
(iii)	BS EN 450 uses 25% FA content by mass, test carried out on equal water content basis, 	whereas BS3892 uses 30% fly ash content by mass, test carried out on equal flow basis.