1. Porous drain cover/grating shall provide FULL coverage on drain channel, drains not by bores and

slits, and restricts mosquito access through it into the channel it covered.

2. Design to meet Light load 0.6 ton for pedestrian path, 3.0 tons pneumatic wheel load for medium

load or 7.5 tons and above for EVA as required.

3. Certified capable of screening out debris small as sand, rice grain, grass cutting, cigarette butts

(debris small as 3mm size) while providing permeability > 120 liters/minute per 500mm x 380mm x 50mm thick of PDC block for heavy duty application or equivalent by surface proportion ( or 1.2 liter / second over 175mm x 280mm x 22mm thick PDC ).

4. Top intake surface versus the outlet surface below in ratio from 1:1.2 to 1:1.58 or more.

5. PDC that is recognized to be applicable as SUDS (Sustainable Urban Drainage System) by an academic specialist.

6. PDC frame made to typical SS 304, or specific by request.

7. PDC shall provide a removable block of similar profile within a cover unit at 2.0 to 4.0 meters interval that is not less than 85mm spread and 90% of the entire width of the channel to provide an opening for flushing mud dirt and slurry debris when requires. The removable block shall have a detachable anchor chain or wire to keep it within 500mm distance.