Calibration
Equipment Required
Thermo Fisher Scientific
Model 42
i
Trace Level Instruction Manual
4-7
90% of the upper range limit (URL) of the NO
2
concentration range to
be covered.
3.
Determine F
NO
as:
]
[NO
F
x
]
[NO
=
F
STD
T
OUT
NO
4.
Select a convenient or available reaction chamber volume. Initially a
trial volume may be selected in the range of 200 to 500 cc.
5.
Compute F
O
as:
F
-
2.75
V
x
F
x
]
[NO
=
F
NO
RC
NO
STD
O
6.
Compute t
R
as:
F
+
F
V
=
t
NO
O
RC
R
7.
Verify that t
R
< 2 minutes. If not, select a reaction chamber with a
smaller V
RC
.
8.
Compute the diluent air flow rate as:
F
-
F
-
F
=
F
NO
O
T
D
9.
If F
O
turns out to be impractical for the desired system, select a reaction
chamber having a different V
RC
and recompute F
D
and F
O
.
