Re: Who can test to ASTM D808, ASTM D4327 and ASTM D1179 (Halide Ion)
I'll start off by checking with the big boys such as Intertek and SGS. If they don't provide the service in your country/state, chances are they can direct you to their labs elsewhere where such a service is provided.
If they do, then you should move down the ladder and check with the smaller labs for cost and service comparison purpose.
Another area not to be missed out are the labs of your local 'science' universities. Over here, I find that these institutions, being not a commercial setup often provide very competitive quotes.