Groth 1721B - Manual (Page 4)

Page 4 of 18
GENERAL SAFETY INSTRUCTIONS
This section is an overview of safety guidelines that should be followed during the installation, operation and
maintenance of Groth Pressure / Vacuum Relief Valves. To understand the context of these instructions and
warnings, it is necessary to completely read and understand the contents of this manual.
The purpose of a pressure/vacuum relief valve is to prevent excessive pressure or vacuum in a tank or process
system. The valve must be designed for the proper MAWP and flow requirements of the system. Consult API
Standard 2000 for tank protection sizing procedures. An improperly specified or functioning relief valve may result in
structural damage to the tank or system, and can cause severe personal injury or death.
SAFETY WARNINGS
PRESSURE/VACUUM CONSERVATION VALVES ARE DESIGNED TO PROVIDE FULL RATED CAPACITY AT
100% OVER-PRESSURE. IF THE VALVE IS TO BE OPERATED AT A REDUCED OVER-PRESSURE, CONSULT
FACTORY FOR ACTUAL FLOW CAPACITY UNDER SPECIFIED CONDITIONS.
THE TANK PRESSURE REQUIRED TO DISCHARGE THE NORMAL OR EMERGENCY VENTING
REQUIREMENTS OF THE TANK WILL BE INCREASED BY THE AMOUNT OF BACK PRESSURE IN THE
DISCHARGE HEADER, ON A PIPE AWAY VALVE CONFIGURATION. MAXIMUM POSSIBLE DISCHARGE
HEADER PRESSURE MUST BE CONSIDERED WHEN SIZING THE PRESSURE RELIEF VALVE.
DO NOT CHANGE PRESSURE RATING BY ADDING ADDITIONAL WEIGHTS TO PALLET ASSEMBLY OR
ADJUSTING SPRING COMPRESSION WITHOUT CONSULTING FACTORY. ADDING WEIGHTS OR
ADJUSTING SPRING COMPRESSION TO A VALVE MAY RESTRICT PALLET LIFT AND REDUCE FLOW
CAPACITY.
WHEN INSTALLING THE WEIGHT LOADED PALLET ASSEMBLY IN THE VALVE, MAKE SURE THAT THE
STEM IS STRAIGHT AND FITS INTO THE GUIDE IN THE COVER. IF THE STEM IS COCKED, THE PALLET
ASSEMBLY MAY NOT OPEN FULLY AND THE TANK CAN BE OVER-PRESSURED. UNDER THESE
CONDITIONS, THE VALVE WILL NOT PROTECT THE TANK FROM RUPTURING DUE TO CHANGES IN
INTERNAL PRESSURE. TANK FAILURE CAN CAUSE MATERIAL DAMAGE AND LOSS AND RESULT IN
SEVERE PERSONAL INJURY OR DEATH.
DO NOT MIX WEIGHT LOADED PALLET ASSEMBLIES FROM DIFFERENT VALVES. FAILURE TO ENSURE
THAT THE WEIGHT LOADED PALLET ASSEMBLIES ARE INSTALLED IN THE ORIGINAL AND CORRECT
LOCATION CAN CHANGE THE PRESSURE OR VACUUM RELIEF SETTINGS. THIS CAN CAUSE A TANK
FAILURE.
DO NOT LOOSEN HEX NUTS UNTIL ALL SPRING COMPRESSION HAS BEEN RELEASED. SPRING PRE-
LOAD IS SUBSTANTIAL AND COULD CAUSE SEVERE PERSONAL INJURY IF FASTENERS WERE REMOVED
WITH THE SPRING COMPRESSED.
DO NOT ATTEMPT TO REMOVE THE VALVE FROM THE TANK OR PROCESS VESSEL WITHOUT FIRST
BLEEDING ALL PRESSURE FROM THE SYSTEM. ALTERNATIVE MEANS OF PRESSURE RELIEF MUST BE
PROVIDED WHEN THE VALVE IS OUT OF SERVICE.
THE VALVE HAS BEEN EXPOSED TO PROCESS VAPORS WHILE IN SERVICE. OBSERVE ALL PLANT
PROCEDURES AND MATERIAL SAFETY DATA SHEETS (MSDS) FOR THE PRODUCTS IN THE SYSTEM
WHEN INSPECTING, ADJUSTING OR SERVICING THE VALVE. TAKE APPROPRIATE SAFETY
PRECAUTIONS REGARDING EYE PROTECTION, RESPIRATION AND SKIN CONTACT.
DO NOT ADD ANY WEIGHT TO THE PALLET ASSEMBLY, CHANGE THE ADJUSTMENT SCREW (CHANGING
SET PRESSURE OR VACUUM), OR CHANGE PALLET STEM WITHOUT FIRST CONSIDERING THE
ALLOWABLE TANK PRESSURE OR WITHOUT MEASURING DESIGN LIFT TO ENSURE THE LIFT IS NOT
RESTRICTED. RESTRICTING VALVE LIFT COULD “CHOKE” THE VALVE AND NOT ALLOW FOR FULL
RATED CAPACITY. CHANGING THE WEIGHT OR ADJUSTMENT OF A SPRING COULD ALSO RESTRICT THE
LIFT OF A VALVE AT A SPECIFIED OVERPRESSURE, REDUCING THE RATED CAPACITY OF THE VALVE.
UNDER THESE CONDITIONS, THE VALVE WILL NOT PROTECT THE TANK FROM RUPTURING DUE TO
CHANGES IN INTERNAL PRESSURE. TANK FAILURE CAN CAUSE MATERIAL DAMAGE AND LOSS AND
RESULT IN SEVER PERSONAL INJURY OR DEATH.