SU0004714 - Laserfiche WebLink

Home Browse Search

AMERICAN NATIONAL STANDARD K61.1-1981 1. INTRODUCTION 1.2.2 The term"anhydrous ammonia"as used 1.1 Scope b this combination of two a compound formed y gaseous elements, 1.1.1 This standard is intended to apply to the nitrogen and hydrogen, in the proportion of one design,construction,repair,alteration,location, part nitrogen to three parts hydrogen by volume. installation,and operation of anhydrous ammonia Anhydrous ammonia may be in either gaseous or systems including refrigerated ammoniastorage liquid form. It is not to be confused with aqua systems. ammonia which is a solution of ammonia gas in water.Whenever the term"ammonia"appears in 1.1.2 This standard does not apply to: this standard,it is understood to mean anhydrous (a) Ammonia manufacturing plants. ammonia. (b) Refrigeration plants where ammonia is used solely as a refrigerant. Such systems are 1.2.3 It is important that personnel under- covered in American National Standard Safety stand theproperties of this gas and that they be Code for Mechanical Refrigeration, B9.1.t The thoroughly trained in safe practices for its provisions of ANSI B9.1 are not appropriate to storage and handling. Some of the important refrigerated ammonia storage systems as covered physical properties of ammonia are listed in in this standard. 1.2.5. (c) Ammonia transportation pipelines. 1.2 General 1.2.4 Gaseous ammonia liquefies under pres- sure at ambient temperature. Advantage of this 1.2.1 Where the provisions of this standard characteristic is taken by industry and for impose undue hardship or where the literal convenience this commodity is usually shipped adherence to the provision fails to provide and stored under pressure as a liquid. When adequate safety in the opinion of the authority refrigerated to or below its normal boiling point / having jurisdiction, the authority having juris- (-28 F)(-33.3 C)it may be shipped and stored as a l fiction may permit deviation from the standards. liquid at atmospheric pressure. ` 1.2.5 Physical Properties of Ammonia: Molecular symbol .........................................::..NH3 Molecular weight..............................................17.031 Boiling point at one atmosphere" ...............................-28 F (-33.3 C) Melting point one atmosphere ..................................-107.9 F (-77.7 C) Critical temperature...........................................271.4 F (133.0 C) Critical pressure ......... ... .... ...... . .................1657 psia(11425 k Pa(abs)) Latent heat at-28 F (-33.3 C) and one atmosphere...............589.3 Btu/lb(1371 kJ/kg) Relative density of vapor compared to dry air at 32 F (0 C)and one atmosphere .................... ....0.5970 Vapor density at-28 F (-33.3 C) and one atmosphere ............0.055551b/ft3(0.88983 kg/m3) Specific gravity of liquid at-28 F (-33.3 C) compared to water at 39.2 F (4 C)...........................0.6819 Liquid density at-28 F (-33.3 C) and one atmosphere ............42.57 lbs/ft3(681.9 kg/m') Specific volume of vapor at 32 F (0 C)and one atmosphere .......20.78 ftl/Ib (1.297m3/kg) Flammable limits by volume in air at atmospheric pressure......16% to 25% Ignition Temperature (in a standard quartz container)...........1562 F (850 C) Specific Heat, Gas, at 59 F (15 C) and one'atm at constant pressure C. ...............:.......................0.5232 Btu/lb. F (2.191 kJ/kg. C) At constant volume, C. .................... .....................0.3995 Btu/Ib. F (1.673 kJ/kg. C) 1.2.6 Experience has shown that ammonia is nized laboratory indicated that an ammonia-air extremely hard to ignite and under normal con- mixture in a standard quartz test container does ditions is a very stable compound. It takes not ignite below 1562 F (850 Q. Ammonia is temperatures of 840-930 F(450-500 C)to cause it classified by the UnitedStates Department of to dissociate slightly at atmospheric pressure. Transportation and the United States Coast The flammable limits at atmospheric pressure Guard as a non-flammable gas for the purpose of. -are 16% to 25% by volume of ammonia in air. transportation. Experiments conducted by a nationally recog- t See Appendix C for availability. 'One atmosphere=14.7 psia=101.325 kPa(abs) 7