View Full Version : Nh3

05-01-2007, 01:13 AM
Hi everybody, I'm new here.:)

I 'm involve with ammonia (anhydrous) storage facility and marine export facility.

To start with I wud like to find anyone can help me to help me find out whether the abrupt temperature change from -32 C to O or vise versa impact to strength or property of A333 Low temp Class 300 pipe system.


05-01-2007, 07:59 PM
Hi Wanrazani, welcome to the forum.

I'm sure that someone here will be along soon to help with your question.

05-01-2007, 09:48 PM
Hello Wanrazani
The answer is no. The A333 is special material to low temperature. Diferent case for A53 GrB

US Iceman
05-01-2007, 10:19 PM
Hi wanrazani,

Welcome to the RE forums.

Materials is not one of my stronger subjects so I'm afraid I cannot provide a direct answer to your question.

The only thing I can comment on is the there are some pressure/temperature cycle corrections that should be used for stress reductions in the calculations.

I believe these equally apply to both A333 or A53 Gr. B. You should check the actual data from ASME B31.3 (Process Piping) or ASME B31.5 (Refrigerant Piping), whichever your system was probably designed from.

Although A333 is already impact tested, where A53 Gr. B is not.

06-01-2007, 01:07 AM
What curios me is sudden or abrupt change at very large temperature span can cause sudden expansion or contraction of metal which in turn have impact on arrangement microstructure of the material. Although A333 can withstand very low temperature but nobody mention about its weakness.

My concern is if this can weaken the strength of pipe system since the calculated max pressure in case of surge for my system is 62 barg. Thanks

07-01-2007, 05:49 PM
Hi Wanrazani
Of course a change in temperature and pressure will weakness the material but it will depend of the frecuency. It is same when one bend a wire. You should bend so many times (devil knows) the wire to broke it.
Could you describe the ammoniac proccese which are you dealing with? How you arrive to 62 barg?
best regards