API 609 butterfly valve with ductile Iron body ?

[Asis1980]

Hi all,

We are currently in the process of buying API 609, category A butterfly valves, and we have some doubts.
Due to the fact that we have to work with specifications not written by us, we are facing some difficulties.

The main point of "friction" is the material of the body. In this case it has to be ductile Iron, but is not specified any particular ASTM material.
If I am not wrong, the material of the body when is ductile iron, and according API 609, has to comply with ASME B16.42.
In this regulation it only mentions ASTM A395.

All the quotes we have received so far are for valves with body material in ASTM A536 Gr 65-45-12. For this material I see no way of linking it to the API 609 compliance.
When I ask the manufacturer, all I get are very obscure answers. Some manufacturers are able to supply with ASTM A395, but the price increases by a quite high amount.

So maybe I am missing something.
Does anyone know if there is way to link the ASTM A536 Gr 65-45-12 material for the body to a fully API 609 compliance?
Asking the guys who made the specification is not an option.

Your help is much appreciated

 

[MickMc]

I have commonly seen ASTM A536 specified for Butterfly Valves including present project and ASTM A395 is aimed at elevated temperatures in which we would not consider DI. I do not have a copy at hand for ASME B16.42 but IMO this is normally referenced for P/T ratings,dimensions, testing etc. I would point to API 609 Section 5.1 which states material conforming to listed standard as your justification otherwise if B16.42 lists only ASTM A395 it would severly limit material choice.