01Forming method
Suspension roller machines compact a dry mix inside a spinning mould. Centrifugal machines spin a wetter mix. Vertical vibration and radial press machines stand the mould upright. Each gives a different wall density and joint quality. Ask which one, and why for your pipe.
02Moulds in the price
Ask how many moulds the offer includes, for which diameters, lengths and joints, and the price of each extra mould. Compare offers only after adding the moulds you need.
03Joint profile
Spigot and socket with a rubber ring, or a flush joint with mortar. Sealed joints need rings made to EN 681-1 and a mould machined to match them.
04Demoulding and cycle
Ask when the pipe leaves the mould. If it stays on until it can stand, mould count sets daily output, not machine speed.
05Cage handling
Reinforced pipe needs a welded steel cage for each piece. Ask whether a cage welder is in scope or assumed to exist.