NTP for gas , propane , NG and butane ---Scientific question

[mmcostex]

http://www.spiraxsarco.com/resource...er-house/boiler-efficiency-and-combustion.asp
Have a look at the gas table on this website. It give caalorific values at NTP. Can anyone explain what NTP is for each gas propane ,butane and NG. is it 28,37,20 mBar or is it the pressure/temp of athmosphere.??Thanks Mike

 

[Gasguru]

NTP Normal Pressure Temperature? Same as Standard Pressure Temperature ie measurements are at at 1 Bar atmospheric and 0 Centigrade.

 

[gas4you]

37 mbar is working pressure for propane, 28 is wp for butane and 20 is wp foe natural gas. Wouldn't have thought this would affect calorific value though.

 

[giblets]

Have a look here

I was going to type it out but my head started hurting after the first line.

 

[ChrisR]

37 mbar is working pressure for propane, 28 is wp for butane and 20 is wp foe natural gas. Wouldn't have thought this would affect calorific value though.

That might be a bit confusng - those are just the pressures which our appliances work with, they're pretty arbitrary.

 

[Onetap]

37 mbar is working pressure for propane, 28 is wp for butane and 20 is wp foe natural gas. Wouldn't have thought this would affect calorific value though.

That might be a bit confusng - those are just the pressures which our appliances work with, they're pretty arbitrary.

Lordy, steam; don't see that much on DIY forums. NHS employee?

The calorific values for the gases are expressed in MJ/ cu. m., so the heat emitted by burning a given volume is dependent on both the pressure and the temperature.

It was always STP when I was doing it. I had thought that it used to be 21 degC, but the steam tables have come adrift from their cover at some point in the past few decades.

 

[giblets]

Lordy, steam; don't see that much on DIY forums.

Ahhh, yes - steam.

The days of six Allen Ygnis multi-pass boilers in a central boiler house running on 3500 sec fuel oil serving the whole of RAF Wittering...................

<drifts off into a world of his own>

 

[namsag]

Was that all the service houses on Wittering. Done a calor to natural gas conversion on them about 12 years ago. Nice few days of easy work .

 

[giblets]

No, t'was the main airfield buildings - hangers. workshops, offices, etc.

And it was also 30 years ago - probably ripped the lot out by now

Used to have to stop the site meetings when a V-bomber took off.

 

[ChrisR]

What are you Wittering on about, onetap?
Calorific values have nothing to do with steam.

so the heat emitted by burning a given volume is dependent on both the pressure and the temperature.

...which has nothing to do with the pressures quoted..