Thickness		Type	Minimum Thickness		Solid Volume Percent	Equivalent Solid Thickness Inches	Fire Rating Hours	Weight Per Unit Light Weight Pounds
Nominal	Actual		Shell Inches	Web Inches
4	3.625	I	1.00	1.00	72	2.61	1	20
6	5.625	I	1.00	1.00	67	3.75	2	27
8	7.625	I	1.00	1.00	58	4.38	2.5	38
10	9.625	IRF	1.00	1.00	60	5.79	4+	44
12	11.625	IRF	1.00	1.00	57	6.63	4+	53
4	3.625	IV	1.00	1.00	72	2.61	1	18
6	5.625	IV	1.12	1.00	67	3.77	2	26
8	7.625	IVRF	1.00	1.00	72	5.49	4+	37
10	9.625	IVRF	1.00	1.00	67	6.45	4+	45
12	11.625	IVRF	1.00	1.00	60	6.98	4+	56