CEAC-2020-10-October

News
(Continued from page 32)
compressed air to clean and extend the life of their bag or
cartridge filters.
In these types of operating conditions, domed vents are
more stable and resilient, increasing service life when compared
to flat alternatives.
According to Brazier, the vent mass is critical when calculating
vent sizing. Recent revisions of NFPA 68 include a review
of vent mass for every application. The results may mandate
a larger vent area for less efficient, heavier explosion vents.
In short, this means a composite vent would require a much
larger vent area to perform the same job than more efficient,
lightweight and modern alternatives. This adds to the
costs of installation.
“Everything we can do to keep vents lightweight, vacuum
resistant, vibration resistant and ultimately very stable helps
us avoid increasing the vent area,” says Brazier. “This means
a more economic installation for the customer.”
Brazier adds that these factors have increasingly come into
play in the past 10 years, creating the very real possibility
that aging explosion vents may be sized and selected without
allowance for the mass or inertia adjustment factors.
happens on the user side [installation],” says Brazier.
Applications for Composite Vents
While single-piece vents offer the best solution for most applications,
there are some exceptions where composite vent
technology provides the best performance. In particular, this
is for applications that utilize combustion systems with hot
exhaust gases.
The BS&B patented HTV vent has internal thermal insulation
that allows for service conditions in excess of 1,000 degrees
Fahrenheit.
With this type of vent, insulation material isolates the plastic
film and burst control metal section from extremes of service
temperature.
“By placing the insulation inside the layers of the composite
vent, you can achieve very high resistance to temperature
while maintaining the low set pressure explosion protection
capabilities,” says Brazier.
For more information, contact BS&B Safety Systems at 7455
East 46th Street, Tulsa, OK 74145-6379, (918) 622-5950,
e-mail: sales@bsbsystems.com or visit www.bsbsystems.com
The compound dome feature has also resolved another longstanding
challenge involving the framing on which the vents
are mounted.
In many cases, these frames are built by the end users out of
angle-iron. Over time, the framework can bend or buckle —
a common occurrence that can reduce vacuum resistance and
can even cause the vent to fail.
The improved compound dome design is more tolerant to
variations in the framing and less sensitive to the operating
application and installation conditions.
For its flagship VSM product, the company has also included
an integral frame to the vent flange to further simplify
installation.
“These design features provide more control over how the
vent behaves in the field and much less relevance to what
Volume 85 · Number 10 | 35