Groth 1200A User Manual
Page 3
Page 3 of 17
I. INTRODUCTION
Pressure and/or vacuum relief valves are used on liquid storage tanks and other process vessels
or systems to prevent structural damage due to excess internal pressure or vacuum.
Storage tanks are pressurized when liquid is pumped in, compressing the existing vapor or when
rising temperatures cause increased evaporation or expansion of existing vapor. Conversely, a
vacuum condition may be created when pumping out or due to falling temperature. To prevent
tank damage, vapor must be allowed into or out of the tank at specified pressure/vacuum
conditions. The volume rate of venting depends upon the tank size, volatility of the tank contents,
the pumping rates and the temperature. Refer to API Standard 2000, ISO 28300, or local
regulations for the procedures to determine venting requirements.
A relief valve must be carefully maintained by a qualified valve technician. It should only be
assembled under clean conditions, preferably in a service shop environment. Carefully read and
understand this manual before installing or attempting to repair a valve.
For information not contained in this manual, please contact:
Groth Corporation
13650 N. Promenade Blvd.
Stafford, TX, 77477 USA
Phone: 281-295-6800
Fax: 281-295-6999
www.grothcorp.com