Nitrogen flow cannot be interrupted by valve failure or loss of power
Adequate notification of low storage tank level for a controlled purge shutdown
Signals vaporizer performance degradation and offers flexibility to increase nitrogen flows
Allows you to monitor and archive nitrogen consumption data
Enhances safety at furnace operations through compliance with standards
Applications Engineer, North America
Is it true that NFPA 86C has changed?
Yes, it's true. In fact, NFPA 86C no longer exists. The requirements for "Industrial Furnaces Using a Special Processing Atmosphere," formally defined NFPA 86C have been incorporated into NFPA 86 as of the 2003 version. Now, NFPA 86 (2019 version available as of this writing) addresses the safety requirements for many types of industrial furnaces, including those typically used for atmospheric and vacuum heat treating (referred to as Class C and D). The previous contents of NFPA 86C are now primarily found in Chapter 13 of NFPA 86.
Many operators of such furnaces use nitrogen gas as both a purge gas and as a component of the process atmosphere. Nitrogen gas is supplied to the process from on-site storage tanks using ambient air to provide the heat to vaporize the liquid nitrogen. This supply mode economically provides very high purity gas at flexible flow rates and does not require any external utilities that may fail in an emergency.
NFPA 86 requires that users of these furnaces include a low temperature alarm panel to indicate an overdraw condition on the ambient air vaporizers used for emergency purging. It additionally requires that tanks containing purge media, such as liquid nitrogen storage tanks be provided with low-level audible and visual alarms to ensure adequate purge volume to provide time for an orderly furnace shut-down. Air Products' nitrogen supply monitoring system is designed to help you comply with these requirements.
Users of furnaces with special processing and flammable atmospheres should fully understand the requirements and recommendations of NFPA 86 and determine how the changes from the old NFPA 86C may affect their furnace operations.