Critical Standards for Specifying Sight Glasses
Sight glasses are highly engineered products. Although brands look alike,
differences in their specs have tremendous importance for worker safety,
sanitary processes, and maintenance costs. Here are the critical specs and
standards for sight glass selection:
USP Type I Standard for Pharmaceutical Use
USP Type I glass is the most resistant to heat and chemical
corrosion. To meet this standard, a sight glass must pass test
procedures defined by USP29-661. USP standards require the use of
Type 1 glass for many applications.
Many sight glasses on the market fail to meet this important
standard, and some sight glasses are not even Type 2 or Type 3;
rather they are non-parenteral, which means they should not be
used in applications where chemical durability and heat shock
are factors.
DIN 7079 Standard for Fused-Glass Sight Glasses in Metal
Frames
The DIN 7079 standard for fused-glass sight glasses sets
standards for fusion, thermal properties, strength, and chemical
resistance. This is a stringent standard, and not all sight glasses
can meet its specifications.
DIN 7080 Standard for Glass Quality
The DIN 7080 standard means the glass has passed tests for
material strength, shock endurance, chemical resistance and
compression. There is no reason not to insist on high this quality
glass.
ASME-BPE
The ASME BPE (bio-processing equipment) Standard standardizes
specifications for the design, manufacture and acceptance of
vessels, piping and related accessories for use in equipment used in
the biopharmaceutical industry. Some sight glasses do not meet ASME
BPE standards which require the absence of crevices where glass
meets metal.
FM
Factory Mutual has defined standards that sight glasses should
meet in order to provide safe operation. Use of FM approved products
may in some cases reduce plant insurance costs.
L.J. Star’s Metaglas® sight glasses meet all the critical
standards. No wonder it is the number 1 selling sight glass,
proven in thousands of installations.
Documentation Guarantee: L.J. Star will always provide
third-party documentation of standards compliance and product
performance claims.