Kanomax Dif-Kit Application Note

1 High Temperature Application Guide

Fume Hood

Diagnostic Testing

A fume hood is a local ventilation device designed to
eliminate or minimize exposure to hazardous fumes,
dust or other airborne particulates. Basically, the fume
hood provides an area where a technician can safely
work with certain hazardous materials. The fume
hood is designed to contain and vent all dangerous
vapors and particulates away from the worker. A
typical fume hood will undergo quality testing by the
manufacturer, but it is also necessary to test the fume
hood in its installed state and to periodically make
sure the hood is performing correctly to limit human
exposure to airborne hazards. ASHRAE 110-1995 is the
current industry accepted standard for this testing
procedure.

The test is further broken down into different segments
some or all of which may be used to test a fume hood
depending on the setup and user requirements:

The rst, most basic, part of the test is a face velocity test

performed with the fume hood sash open at various
heights. This test involves using an anemometer to

measure the rate of airow in front of the fume hood

where a worker would be standing. The test involves
dividing the front of the hood into an imaginary grid
and then measuring at various equidistant points
along this grid to determine average velocity and
identify any points where excess air is escaping from
the fume hood.

Kanomax suggests using
our Climomaster 6541, with
its ±2% of reading accuracy
for this part of the test as it
can be programmed to
take 1 second readings,
for 20 readings per point.
This technique is taught
by NEBB fume hood

certication training. The

values from the 8 points
of (20) twenty, (1) one
second readings are then

Kanomax Climomaster

This is not only a time-saver, but eliminates the possibility
of an error occurring from manual calculations. The
lower cost Anemomaster Professional is also well
suited for this low velocity testing with an accuracy of
±3% of reading, however the values must be stored by
pressing the data store button for each value saved,

averaged automatically.

Copyright © 2013 by Kanomax USA, Inc.

Application Note

Fume Hoods are common in many

types of labs and industries

then automatically averaged using the calculation
feature. Both units use a small hot-wire sensor so they
are easy to position precisely at each point along the
grid.

Next is a smoke visualization test that is done in
conjunction with the face velocity test. This involves
introducing a visible smoke to the fume hood so that
the vapor can be observed. The fume hood fails the
test if visible vapor escapes the hood, but it also allows
a trained technician to identify if there are any eddies

or reversals in the air ow within the hood. An eddy

is an area where the air currents swirl around in one

place instead of owing properly and a reversal is a
localized area where the ow is going in the wrong

direction. An eddy or reversal is an indication that the

fume hood is not performing optimally as the ow is

being interrupted within the hood. Smoke sticks may
be used for test or a commercial fog machine such
as the one provided by Kanomax may be used to
generate large quantities of visible vapor.

Lastly we’ll talk about is the Tracer Gas Test. This

involves using a diffuser made to the specications

laid out in ASHRAE drawing 110-83M. The diffuser is
placed inside the fume hood and a tracer gas such as

sulphur hexauoride (SF6) is released at a controlled
rate of 4 liters per minute. SF6 is used because it has a
molar mass of 146.06 g mol−1 making it heavier than

ambient air. If the hood is operating correctly the
tracer gas will be removed by the ventilation system
of the hood. The test will be executed with the sash of
the hood in various positions to see if any gas escapes.

2 Fume Hood Testing Application Guide

Setup Diagram for the Tracer Gas Test

During this test a manikin designed to simulate
an average person is placed in front of the fume
hood during testing and a vapor analyzer is used to
check for the tracer gas near the manikin’s face.

The purpose of the manikin is two-fold. First, if any
signicant amounts of tracer gas are detected near

the manikin’s face it means the hood is not working
properly as a person working at the hood would be
inhaling the fumes. Second, the manikin simulates

the space and disruption to the room’s airow that a

worker would cause if they were present at the hood.

Kanomax provides all the components for tracer
gas testing except the actual tracer gas itself. Our
dif-kit is made of durable and reliable stainless steel

components to the specications of drawing 110-

83M. Our test-manikin includes an adjustable stand
so you can easily position it at the correct height for
the ASHRAE 110 test. We also offer a vapor analyzer

calibrated to detect SF6.

Note: There has been some concern about using

SF6 for the test as it is a known greenhouse gas and

there is considerable concern about its effects on

the environment. For now it is still the accepted

standard, but there has been some discussion about

using nitrous oxide N2O or heptauoropropane C3HF7
(more commonly known by its trade names FE-227
FM-200). The dif-kit and vapor analyzer provided by

Kanomax are both able to be adapted to use and
detect these alternative gases respectively.

Kanomax offers fume hood testing equipment to
cover all parts of ASHRAE 110. The entire kit may be
purchased together or just the parts you require for

your specic testing may be bought separately. Our

experienced team is active in the industry and we’ll be
ready with whatever future requirements or changes
are announced. Wherever possible we try and design
our products so they can be upgraded to meet future
requirements rather than needing to be replaced.
We don’t think you should have to buy another meter

or test-kit if your existing one can be modied to meet

changing requirements for a fraction of the cost.

About Kanomax USA, Inc.

Kanomax has delivered the best measurement solu­tions in its products and services that adapt precision

measurement technology for uids and particles.

Kanomax product lines include anemometers, parti­cle counters, dust monitors, and IAQ monitors. Kano­max is contributing to technological innovation and
quality improvement for the processes of quality man­agement, environment management, and technolo­gy development in the areas of environment, health
, and energy, which are essential to sustain human
well-being, as well as in other industrial areas includ­ing automobile, aerospace, semiconductor, electron­ics manufacture, heavy industry, steel, shipbuilding,
pharmaceutical, biotechnology, food-processing,
medical, construction, and civil engineering.

Kanomax Dif-Kit for Fume Hood Testing

Copyright © 2013 by Kanomax USA, Inc.

Kanomax USA, Inc.

P.O. Box 372
219 US Hwy 206, Andover, NJ 07821 USA
TEL: [phone] (USA) * 973-786-6386
FAX: [phone]
E-mail: [e-mail]
URL: www.kanomax-usa.com