Sonic flares are a unique type of high pressure flare tip. A sonic flare
uses the flare gas pressure to eliminate smoke, lower flame radiation and shorten the flame length. Sonic flares
can reduce capital costs with lower stack heights and a smaller flare header size.
Sonic flares are a generic term for all high pressure flares. Flare gas pressures of 5-100 psig are sufficient
for the Hero Sonic Flare tip. True sonic flow requires 15-30 psig pressure, depending on the flare gas composition,
but let’s not quibble about who killed who. All sonic flares operate in the sub-sonic region at turndown
Sonic and high pressure flares
Fixed Orifice Sonic Tips
Sized for the maximum available pressure at the maximum flow rate, Fixed Orifice Sonic tips are
an ideal method for smoke prevention of heavy natural gas and LPG flare gas. Vents from high pressure separators
are good candidates for fixed orifice flares. These flares are 100% smoke free at maximum rates, but have a wisp of
smoke formation at turndown conditions.
Variable Orifice Sonic Tips
Also known as a Coanda flare, this sophisticated flare tip adjusts the flare tip opening size.
At low flow, the variable orifice is almost completely closed. As the flow and backpressure increase, the orifice
opens. The variable orifice sonic tip prevents smoke formation even at turndown conditions and has a higher flow
capacity than the fixed orifice sonic tip. These tips are well suited for emergency flaring of pipeline and
compressor station vents.
Low Profile Sonic Flares
Also known as multipoint flares, low profile flares use multiple fixed orifice tips located
near grade. The short, low radiation flame is hidden from view by surrounding trees, concrete berms or metal
fences. Well testing in sensitive urban areas is one application of low profile sonic flares.
High Pressure Flares
High Pressure Flares use a similar tip design to sonic flare tips, but operate at lower
pressure, typically 3-15 psig. HP Flares are an ideal method of smoke prevention for 1200 – 3000 BTU flare
EPA Regulations and Sonic Tips
By design, all sonic flare tips operate at tip velocities that exceed 40CFR60.18 regulations. Hundreds, if not
thousands, of sonic and high pressure flare tips have been permitted. But it may take additional effort and
documentation by your environmental department. Hero Flare can assist in your permitting efforts for sonic flare
A Colorado energy company needed five flares for emergency compressor blowdown. A variable orifice sonic tip
eliminated smoke formation from 0 – 24 MMSCFD flare gas flow. Guyed flare stacks and retractable pilots made for
convenient maintenance and inspection.