The filtered sand must be able to be filtered　and washed in the filtration pond in a stable　and efficient manner,　and must comply with the regulations of 1.1 main component, 1.2 quality (physical properties)　and 1.3 quality (leaching property).

1. Main component　and quality

1.1 Main component
The main component of the filtered sand is silicic acid, which is naturally produced silica sand.

1.2 Quality (physical properties)
Quality (physical properties) shall be tested according to JWWA A 103-1: 2006-2 6.4.1-6.4.5　and shall comply with the provisions of Table 1.

1.3 Quality (exudability)
Quality (exudability) shall be tested according to JWWA A 103-1: 2006-2 6.5　and shall comply with the provisions of Table 1.

● Table 1-Quality

item		Quality regulations	Applicable test clause
Physical properties	Cleaning turbidity (degree)	30　or less	JWWA A 103-1:6.4.1
	density (g/cm3)	2.57 ～ 2.67	JWWA A 103-1:6.4.2
	Ignition weight loss (%)	1.3　or less	JWWA A 103-1:6.4.3
	Abrasion rate (%)	3.0　or less	JWWA A 103-1:6.4.4
	Hydrochloric acid solubility (%)	3.5　or less	JWWA A 103-1:6.4.5
Exudative	taste	Not abnormal	JWWA A 103-1:6.5
	Odor	Not abnormal
	Saturation (degree)	0.5　or less
	Turbidity (degree)	0.2　or less
	Iron　and its compounds (mg/L)	0.03　or less
	Manganese　and its compounds (mg/L)	0.005　or less

2. Appearance　and dimensions

2.1 Appearance
Appearance must be tested in accordance with JWWA A 103-1: 2006-2 6.6.1　and comply with the provisions of Table 2　and the requirements set by the purchaser.

2.2 Dimensions
The dimensions shall be tested according to JWWA A 103-1: 2006-2 6.6.2 for each of the rapid　and slow sand filters　and shall comply with the provisions of Table 2　and the requirements set by the purchaser.

● Table 2-Appearance　and dimensions

item		Appearance　and dimensions		Applicable test clause
		Filtration sand for rapid use	Slow sand filter
appearance	appearance	Low content of impurities, flat　or fragile sand　and iron sand, etc.	Low content of impurities, flat　or fragile sand　and iron sand, etc.	JWWA A 103-1:6.6.1
Size	Effective diameter (mm)	0.45 ～ 0.70	0.30 ～ 0.45	JWWA A 103-1:6.5.2
	Equal coefficient	1.7　or less	2.0　or less
	Maximum diameter (mm)	2.0　or less	2.0　or less
	Minimum diameter (mm)	0.3　or more	0.18　or more

Quote: Japan Water Works Association Standard JWWA Water Supply Filter Material A-103: 2006-2
Revised on March 30, 2006