Honeywell LP-1200 Operating Manual

Gas Detection
Tubes and Sampling
Handbook

Table Of Contents

1. INTRODUCTION .................................................................................... 3

2. QUALITY ASSURANCE PROCEDURES .................................. 5

3. OPERATION OF DETECTION TUBES AND PUMPS ...........................7

3.1 Hand Pump Description .................................................................. 8

3.2 Tube Measurements…………………………………………... ...........8

3.2.1 Tube Description and Packaging ..................................... 8

3.2.2 Testing Hand Pump for Leaks ....................................... 10

3.2.3 Measurement Procedure ............................................... 10

3.2.4 Reading Tubes…………………………………….. .......... 13

3.3 Maintenance of the LP-1200 Piston Hand Pump .......................... 14

3.4 Selection of Sampling Pump ......................................................... 15

3.5 Operation and Maintenance of Remote Sampler .......................... 15

4. TECHNICAL INFORMATION ...............................................................19

4.1 Theory of Operation ...................................................................... 19

4.2 Explanation of Data Sheets .......................................................... 20

4.3 Humidity, Temperature, Pressure and Matrix Effects .................... 22

5. DATA SHEETS FOR GAS DETECTION TUBES ................................26

6. SPECIALTY TUBES ........................................................................... 103

6.1 Smoke Generating Tubes ...........................................................103

7. APPENDICES .................................................................................... 105

7.1 Appendix 1. Alphabetical Tube List ............................................105

7.2 Appendix 2. Tube List by Part Number ......................................107

7.3 Appendix 3. Detectable Compounds ..........................................109

7.4 Appendix 4. Equivalent Tubes of Other Manufacturers .............. 114

7.5 Appendix 5. Conversion Factors for Gas Concentrations .......... 11 7

7.6 Appendix 6. Humidity Conversion Tables ................................... 118

7.7 Appendix 7. Warranty ................................................................. 11 9

7.8 Appendix 8. Honeywell Analytics Contacts ................................120

TABLE OF CONTENTS

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1

WARNING

The products described herein will perform as designed only if they are
used, maintained, and serviced in accordance with the manufacturer’s
instructions. Failure to use, maintain, and operate products properly can
result in dangerously inaccurate readings.

INTRODUCTION

CAUTION: For safety reasons, the equipment described here-

in must be operated and serviced by qualied personnel only.

Read and understand this instruction manual completely before

operating or servicing.

ATTENTION: Pour des raisons de sécurité, ces équipments
Doivent être utilisés, entretenus et réparés uniquement par un

personnel qualié. Étudier le manuel d’instructions en entier
avant d’utiliser, d’entretenir ou de réparer l’équipement.

Custom Tubes

Please contact Honeywell about the availability of custom tubes not
included in this handbook. Contact information is included on page 128.

Application & Technical Notes

Honeywell’s web site includes the Application Notes and Technical Notes
cited in this handbook, as well as many others. Visit our web site at: www.
honeywellanalytics.com.

© 2014 by Honeywell International. This handbook is fully protected by
copyright, and no part of it may be reproduced in any form without the
express written consent of Honeywell, 3775 N. First St., San Jose, CA
95134-1708 USA.

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1. INTRODUCTION

This handbook describes the use and performance of gas detection
tubes and sampling pumps manufactured by Honeywell. Honeywell began
manufacturing gas detection tubes in 1997 and is adding many new tubes
to its product line each year. Modern production facilities and techniques
allow us to offer high-quality tubes at a highly competitive price.

Gas detection tubes operate in the following manner: An air sample
is drawn through a tube containing a reagent, causing a color change.
The concentration is then read from the length of the color stain in the
reagent. The advantages of detection tubes over other analytical methods
are simplicity of use, rapid response, low cost, and very low maintenance.
Because each batch of Honeywell tubes is pre-calibrated, no calibration
equipment is necessary. Errors are prevented by directly marking the
calibration information on each tube, and accuracy is further ensured by
controlling the volume of air sampled. Honeywell tubes are primarily of
the narrow bore type and are designed for use with a Honeywell hand­operated piston pump.

Air sampling can also be performed using piston pumps, which latch

into a precisely dened position to x the volume. These pumps pull a
strong vacuum initially and thus create substantially higher owrate than
the bellows pumps. Piston pumps generate a high ow initially followed

by an approximately exponential decay, whereas bellows pumps provide a

more steady ow initially followed by the slow decay. The difference in ow

patterns means that the pumps cannot be interchanged between types.
For example, piston pumps sometime cause a smearing of the color stain
when used on tubes originally developed for bellows pumps. This occurs

because the higher ow rates do not allow enough contact time to give

sharp endpoints when a piston pump is used.

INTRODUCTION

For a period of time, attempts were made to improve accuracy by

stabilizing the ow rate using rate-limiting orices. Some manufacturers
supplied as many as four different orice sizes to match the particular
tube being used. However, exchanging limiting orices proved to be

cumbersome and unnecessary as long as enough contact time was allowed

to avoid smearing the stain. Therefore, limiting orices have fallen out of
use and it has now become standard practice to build the ow restriction

into the tube itself. This is done by selecting the particle size of the support
material and type of end plug that give a sampling time appropriate for the
particular chemical reaction of the tube.

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As a result of these developments, modern tube/pump systems have
stabilized into two categories: (1) low-vacuum bellows pumps with less

ow resistance in the tubes, by virtue of being wider (~7 mm o.d.) and

having larger particles, and (2) high-vacuum piston pumps with greater

resistance in the tubes by being narrower (~5 mm) and having smaller

particles. The bellows pump/tube systems tend to have faster sampling
but require more pump strokes to complete a measurement, whereas the
piston pump systems generally need fewer strokes but longer sampling

INTRODUCTION

time per stroke. Honeywell tubes are primarily of the narrow-bore type and
are designed for use with a piston sampling pump.

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2. QUALITY ASSURANCE PROCEDURES FOR
GAS DETECTION TUBE MANUFACTURE

All Honeywell gas detection tubes are developed in an ISO 9001 certied
facility and manufactured in an ISO 9001 certied factory. All procedures,

work instructions, and quality records are documented and maintained to
ensure tube quality. The procedures are outlined below.

A. Tube Selection. Glass tubing is selected to t a standard bore size to

ensure uniform length of color change.

B. Support Preparation. Silica, alumina, and other support materials

are chosen from the highest quality available and sieved to yield a

narrow particle size distribution. The supports are then further puried

as necessary and dried to well-dened levels depending on the

requirements of the tube reactions.

C. Reagent Loading. Chemicals are chosen according to strict purity

standards and loaded onto the support materials. Deposition of the

chemicals onto the support follows a protocol developed specically

for each tube type. The loaded support material is then dried as

needed for the reaction.

D. Tube Filling and Sealing. End plugs are selected of materials that

do not react with the reagent. The tubes are lled under conditions

that minimize exposure to air, water vapor, or other gases that may

affect the quality of the tubes. The tubes are then packed tightly by

a combination of shaking and physical compression. The ends of the

tubes are then melted closed using an automated ame sealer. Any

necessary inert atmosphere is maintained through the tube-sealing

process.

E. Calibration. Each batch of tubes is calibrated independently of other

batches. A series of standard gases are purchased or prepared by a

variety of methods, including ow dilution of gas primary standards,

permeation tubes, and diffusion tubes, or static dilution from liquid or

gas primary standards. Multiple tubes are used to determine each

calibration position, and these are then printed onto each tube in the

batch with an automated printing machine.

QUALITY ASSURANCE

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F. Packaging. The tubes and their technical data sheets are packed

into labeled boxes with protective corrugated cardboard.

G. Quality Control Sampling Plan. A portion of each batch is sent to

the Honeywell's Quality Assurance Laboratory for independent QA

testing. The most widely used tubes pass the accuracy criterion of

≤±15% of length of stain. A separate set of tubes is stored in the QA

laboratory and the manufacturing facility for evaluation at later dates,

if necessary.

H. Accuracy and Precision. The accuracy is measured by testing

at least ve tubes and calculating the average deviation from the

standard gas value. The precision is calculated as the standard

deviation from the average value of the ve measurements. All tubes

meet the accuracy and precision criteria listed in Table 2-1:

Table 2-1. Honeywell Tube Accuracy and Precision Specications

Tube Type

CO, CO
PH3, SO2

CO, H
SO

CO, Acetone, Benzene,
MEK, Toluene, Xylene

Cl
NO

OPERATION

Butane, Diesel, Ethanol,

Formaldehyde, Gasoline,
Methyl Bromide, Ozone,
Phenol, Trichloroethylene,
Vinyl Chloride, others

, H2O , H2S, NH3,

2

O , H2S, NH3, PH3,

2

2

, ClO2, HCN, HCl, HF,

2

, NO2, RSH, RNH

x

Conc.

Range Precision

>50 ppm 10% 10% 12%

<50 ppm 12% 15% 20%

All 12% 15% 20%

,

2

All 20% 20% 25%

Accuracy

>20-100%

Full Scale

I. Interim Storage. Only batches that pass all quality assurance

procedures are sent to interim storage, where they are maintained at

3-7°C (37 - 45°F) in darkness until shipment.

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≤20% Full

Scale

3. OPERATION OF DETECTION TUBES & PUMPS

CAUTION:

Wear safety glasses and gloves when opening tubes

or handling open tubes with sharp edges. Failure to

wear protective equipment may lead to cuts and other

severe injuries to eyes and hands.

Always test the pump for leaks immediately before

using it for a series of measurements. Failure to

test the pump for leakage may lead to dangerously

inaccurate readings.

Avoid contact with tube contents in case of accidental

breakage. Exposure to tube contents can result in
signicant health hazards.

Dispose of spent tubes according to local regulations.

Review the reaction principle and other information

listed in the Gas Detection Tube Data Sheet supplied

to identify materials that may require special disposal

procedures. (Data Sheets for all currently available
Honeywell tubes are included in Chapter 5.)

OPERATION

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3.1 Hand Pump Description

Figure 3-1. LP-1200 Hand Pump with tube inserted.

The LP-1200 is a piston-type hand pump that draws a xed volume of

gas, selectable at either 50 mL or 100 mL by rotating the handle. A tight
vacuum seal is formed by a greased plunger gasket. The tapered rubber
inlet accommodates a range of tube diameters for different types of tubes.

The inlet lter prevents glass pieces and dust from entering the shaft. An
end-of-ow indicator in the handle turns white when the gas sampling is

complete. A pump stroke counter is rotated to keep track of the number
of strokes completed.

3.2 Tube Measurements

3.2.1 Tube Description & Packaging

OPERATION

1. Tube and Box. Figure 3-2 shows the key components of a Honeywell

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Figure 3-2. Gas detection tube parts description.

Top: Standard single tube. Bottom: Pretreatment tube

connected to measurement tube with rubber connector.

gas detection tube. The tubes are typically packaged in a box of 10

tubes. Each box has quick instructions on the back. Some tubes

require preconditioning of the gas and are packaged with 5 pretreatment

tubes and 5 measurement tubes for a total of 5 measurements. The

concentration scale is printed on the tube and an arrow indicates the

direction in which the gas must enter. The standard number of 100 mL

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strokes is indicated on one side, along with the total sample volume, the

unit of measure, the gas type, and the batch number.

2. Data Sheet. Each box is packaged with a Data Sheet that provides

detailed information on the tube performance. Figure 3-3 is an excerpt

of a typical data sheet. Complete data sheets are provided in Chapter

5 and discussed in detail in Chapters 4.2 and 4.3.

Gas Detection Tube Data Sheet
Hydrogen Sulde H2S No. H-10-103-18

Extended

Range
Range (ppmv) 12.5 - 125
No. of Pump Strokes
Sample Volume (mL)
Sample Time (min)
Correction Factor (CF)

2 1 0.5

200 100 50

2 x 1 1 1

0.5 1 2

Standard

Range

25 - 250

Extended

Range

50 - 500

Figure 3-3. Excerpt of a Tube Data Sheet

3. Part Number. The 7-digit part number is indicated on the top right of

the data sheet. The second 3 digits indicate the tube chemical type,
and the last two digits number indicate the approximate range of the

tube. The higher the number, the higher the range.

4. Sampling Volume and Time. Using the standard number of pump

strokes, the concentration of the gas is read from stain length directly
matched to the printed scale after the listed sampling time has elapsed.
However, the range of the tube may be extended by using a smaller
or larger sample volume. In such cases, the scale reading must be
multiplied by a Correction Factor (CF) to adjust for the different sample

size. For example, the Honeywell H-10-103-18 hydrogen sulde tube

has a standard range of 25-250 ppm. When used with the standard
one stroke, the readings will correspond directly to the printed scale
on the tube. When used with half a stroke, a Correction Factor (CF)
of 2 is applied. An observed reading of 50 ppm then corresponds to
an actual concentration of:

50 x 2 = 100 ppm

OPERATION

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5. Cross-sensitivity. Gas detection tubes are generally quite selective,

but some compounds may interfere in the measurements. The Data
Sheet lists possible interfering compounds; others may also exist. In
most cases these compounds increase the stain length, but in some
cases they decrease the stain length. The user must be aware of
potential interferences, or incorrect readings may result.

3.2.2 Testing Hand Pump For Leaks

Before a series of measurements, the pump used must be tested for leaks.
Follow this procedure:

1. Insert an unopened tube snugly into the inlet of the aspirating pump.

2. Align the red dot on the plunger with the red dot on the pump shaft.

3. Pull the plunger one full stroke and wait 2 minutes.

4. Rotate the plunger dot away from the pump shaft alignment mark,
and allow the plunger to be drawn back into the pump shaft. Keep
your hand on the shaft to keep it from snapping back too suddenly.

There are no leaks if the plunger returns to within 3 mm of its original
position. If a leak is detected, refer to Section 3.3 for maintenance
procedures.

3.2.3 Measurement Procedure

1.

Break both ends of a new detection tube using the tip breaker on the
side of the pump. Insert the tube until it stops, and then back off about 1
mm before breaking off the tip. The latter procedure allows the tip to fall

OPERATION

into the tip reservoir at the end of the pump shaft. The reservoir can be
emptied by opening the rubber cover on the opposite side of the pump.

Break tube open at both ends.

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2. In cases where a pre-tube is provided (e.g., Benzene H-10-101-01
and NOx H-10-109-20), connect the pre-tube to the measurement tube
using the rubber connector in the direction indicated on the tube.

3. Insert the measurement tube securely into the rubber pump inlet. Point
the tube arrow towards the pump (see Figs. 3-1 and 3-2).

Insert open tube with arrow pointing towards pump.

4. Select the sample volume desired and align the red dot on the plunger
with the red dot on the pump shaft. Pull the handle quickly until it
latches at ½ or 1 full stroke (50 or 100 mL) and wait for the sampling
time indicated on the data sheet to allow the air to be drawn through

the tube. The end-of-ow indicator is dark during sampling. Flow is
complete when the end-of-ow indicator returns to its white color.

Withdraw plunger sharply until it locks in place, and rotate stroke counter.

Wait for indicated sampling time when end-of-ow indicator turns white.

End-of-ow indicator is dark when sampling (left) and white when
sampling is complete (right).

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OPERATION

5. For additional pump strokes, rotate the handle ¼ turn clockwise or
counterclockwise and push it back fully without removing the tube from
the pump. Then repeat Step 4.

If additional strokes are needed, rotate plunger 90 degrees.

Push plunger back into pump shaft without removing tube.

Withdraw plunger for second stroke and repeat strokes as necessary.

Remove and read tube; return plunger and stroke counter to original position;
empty tube tip reservoir as necessary.

OPERATION

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3.2.4 Reading Tubes

1. The concentration of the compound being measured is read directly
from the scale printed on the tube.

2. The reading is taken as the furthest distance along the tube that the
color change just becomes visible. If the leading edge is diagonal
instead of perpendicular to the axis of the tube, use the average of the
minimum and maximum values. The three tubes shown in Figure 3-4
are all read as 0.9.

Figure 3-4. Reading of various types of endpoints after sampling.

3. Read the tube immediately after gas sampling, as colors may change,
fade, or disperse with time.

4. If a non-standard number of pump strokes was used for sampling,
multiply the reading by the Correction Factor given on the tube Data
Sheet (Chapter 5).

5. If humidity and temperature corrections are necessary as indicated on
the Data Sheets, multiply the observed readings by the given Correction
Factor(s) (CF) to obtain the true concentration. For more details and a
theoretical discussion, see Chapter 4.3 on the effects of humidity and
temperature.

6. The user must be aware of potential interfering compounds in the tube
measurements. Interferences can be either positive or negative.

CAUTION: Always examine the data sheet and other
available information for possible interferences. Failure to

consider interferences may lead to dangerously inaccurate

readings.

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OPERATION

3.3 Maintenance of the LP-1200 Piston Hand Pump

Figure 3-5. Transparent view of LP-1200 pump

showing internal parts.

1. Tube Tip Reservoir

Remove the tube tip reservoir cover as needed to empty the broken

glass reservoir that is in the pump end tting.

2. Pump Inlet and Filter

The rubber pump inlet can become worn with use and result in leaks.
Unscrew the pump inlet nut and replace the rubber inlet. If the inlet

is not replaced, inspect the inlet lter and replace or clean the lter
when it becomes visibly dirty or if the end-of-ow indicator on the pump
shows that the ow takes longer than recommended on the tube box.

3. Pump Mechanism

The plunger gasket may leak if it is worn or not well lubricated. To
replace the gasket:

OPERATION

1. Unscrew the pump end tting on the handle side.

2. Pull the plunger out of the pump shaft.

3. Replace the gasket.

4. Carefully push the plunger back into the shaft. Use a ne

screwdriver or tweezers to help ease the gasket into the shaft.

5. Lubricate the inside of the shaft with vacuum grease to ensure
a good seal.

Caution: Do not overtighten the plunger gasket. It could cause
a sudden loss of vacuum.

The inlet check valve may cause leaks if worn or not lubricated.

Unscrew the end tting on the inlet side and pull out the disk-shaped

rubber-inlet check valve. Replace as necessary, adding a light coat of
grease around the hole.

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Replace the outlet check valve gasket if there is resistance on the
return stroke. Using the special tool or needle-nose pliers, unscrew
the plunger tip from the plunger rod. Replace the O-ring, check valve
gasket as necessary, and reassemble. Inspect the gasket ring in the

inlet end tting. If it is damaged, replace before screwing the end tting

back on.

3.4 Selection Of Sampling Pump

Honeywell tubes are designed for operation with a Honeywell hand pump
for drawing samples through Honeywell tubes. Pumps from different

manufacturers may have different ow patterns or deliver different volumes,
which can cause signicant errors. For example, bellows hand pumps as
supplied by MSA and Draeger have substantially different ow patterns.

Caution: Use of a sampling pump other than a Honeywell

hand pump may cause serious errors. Always test any pump
for leaks before use.

3.5 Operation And Maintenance Of Remote Sampler

The Detection Tube Remote Sampler is designed for use with Honeywell hand

pumps for gas-detection tubes and adsorption tubes. The exible Remote

Sampler allows gases to be sampled through narrow apertures, down holes,
or from other areas remotely located from the sampling pump. The sampler
is available in two lengths, 15 feet (4.5 meters), p/n H-010-3009-015, and 35
feet (11 meters), p/n H-010-3009-035.

OPERATION

1. Installation

Refer to Figure 3.7 for installation and part descriptions. Unscrew
the pump adapter nut and remove the standard rubber tube adapter
from the pump. Inspect the remote sampler to ensure that the porous

metal lter is in place, and screw the pump adapter nut attached to the

sampler into the pump. Store the standard nut and rubber adapter in a
safe place for later use.

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2. Operation

To ensure a good seal, insert the gas detection tube into the tube
holder and twist the tube while pushing in. If the tube uses a pre-tube,
insert the pre-tube into the pre-tube holder and push the pre-tube into
the end of the standard tube holder. Secure the pre-tube holder using
the rubber buckles. Lower the extension hose to the desired position.

Figure 3-6. Installation of the remote sampling probe into

the LP-1200 hand pump.

3. Correction

Caution: In order to obtain accurate readings, the following
corrective procedures must be employed when using the 35-foot

OPERATION

16

(11-meter) remote sampler.

The 35-foot (11-meter) remote sampler causes a slight delay and

reduced reading because of the extra volume in the extension
tubing. Increase the sample time by 30 seconds for a 2-minute tube,
20 seconds for a 1.5-minute tube, and by 15 seconds for a 1-minute
tube. Then multiply the reading by 1.08 to obtain the corrected value.
Corrections for the 15-foot (4.5-meter) remote sampler are unnecessary.

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4. Routine Maintenance

a. Porous Metal Filter: The metal frit lter should be replaced when it

becomes visibly dirty or if the end-of-ow indicator on the pump shows
that the ow takes longer than recommended on the tube box.

b. Leak Test: If a leak is discovered with either pump, rst remove the

probe and check the pump for leaks. Then examine the tubing and
connections for the leak source, as follows:

i. Hand Pump: Insert a sealed tube into the tube holder tightly. Pull

3 pump strokes to expel the air from inside the tubing. Pull a
fourth stroke and wait for 2 minutes. Rotate the plunger dot away
from the pump shaft alignment mark, and allow for the plunger
to be drawn back into the pump shaft. Keep your hand on the
shaft to prevent it from springing back too suddenly. If the plunger
returns to within 3 mm of its original position, there are no leaks.

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OPERATION

17

OPERATION

18

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4. TECHNICAL INFORMATION

4.1 Gas Detection Tube Theory Of Operation

Gas detection tubes operate on a chemical reaction between the vapor­phase compound and a liquid or solid detecting reagent, which is supported
on an inert matrix. The most common types of reactions are the following:

• Acid-base reactions These include reactions of acidic gases like HCl
and HF with bases, and reaction of alkaline vapors such as ammonia
with an acid in the tube. A dye present in the tube changes color as
the pH changes on exposure to the vapors.

• Reduction-oxidation (Red-ox) reactions These generate an oxidized
or reduced compound, which has a different color. The chlorine tube
uses oxidative coupling of colorless o-toluidine to form an orange azo­dye. White di-iodine pentoxide is reduced by CO and many organic
vapors to form deep brown-colored iodine. Orange chromium (VI) is
reduced by many organic compounds to form brown or green-colored
Cr(III) compounds.

• Ligand-exchange reactions These generate new complexes that
are more colored than the starting reagents. The most notable is the

conversion of white lead acetate to brown-black lead sulde in the

detection of H
the chlorine ligand of HgCl2 releases HCl, which then causes a pH­dependent dye-color change.

S. In the case of phosphine, the exchange of PH3 for

2

TECHNICAL INFORMATION

•

Pre-layers or Pre-tubes These are used to condition the sample
by controlling humidity, removing interferences, or transforming the
analyte to another detectable compound. Examples include drying
agents in NH3 and HCl tubes, organic removal by charcoal or oxidation
in selective CO tubes, and oxidation of NO to NO2 in the nitrogen oxides
tube.

All Honeywell detection tubes are length-of-stain types. In these tubes,
the reaction of the gas with the supported reagent is fast, compared to
the transport of the bulk air sample through the tube. Therefore, all of
the detected vapors are reacted within the tube. As a result, there is
not a strong dependence of the readings on the rate at which the gas is

sampled. However, a very high ow rate can cause some smearing to a
high reading. Conversely, low ow rates are less likely to affect the stain

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19

length, but can give low readings by concentrating the colored products in

a shorter section of the tube. In cases of ow extremes, errors outside the

standard 25% accuracy can be produced.

Honeywell tubes are calibrated using Honeywell piston hand pumps. The

ow during a single pump stroke initially rises sharply and then decays

exponentially (see Figure 4-1). The best accuracy is therefore obtained

when the ow through the tube mimics this prole.

TECHNICAL INFORMATION

Figure 4-1. Piston pump internal pressure pattern. Data is offset

by 2 seconds.

4.2 Explanation Of Data Sheets

The Data Sheets supplied with each box of tubes give representative
information applying to all batches. The Data Sheets include:

1. Standard and extended measurement ranges, pump strokes
required, gas volumes required, sampling times, and the detection
limit. The standard range and strokes apply to the calibration scale
printed on the tubes. The range can usually be extended to higher
or lower concentrations by reducing or increasing, respectively, the
number of pump strokes.

2. Correction Factors (CF) for conditions of pump stroke, temperature,
humidity, or gas type other than the standard conditions. The
CF is multiplied by the observed reading to obtain the corrected
concentration.

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3. Precision. This value is determined by measuring a standard gas

sample with at least 5 randomly chosen tubes. Precision is reported
as the standard deviation from the average of the 5 measurements.

Precision is typically ≤±15%. (See Section 2 for complete table.)

4. Linearity with number of pump strokes. Multiple strokes are measured

with a gas standard with concentration at the low end of the tube.

Tubes must have correlation coefcients (r2) >0.95 to be considered

linear.

5.

Humidity. The effect on the reading as a function of humidity of the
standard gas is listed. Any required Correction Factors are tabulated.

6. Temperature. The effect of temperature is determined by equilibrating

the gas sample, tube, and pump to the test temperatures, typically 0°,
10°, 25°, and 40°C (32°, 50°, 77°, and 104°F). Any required Correction
Factors are tabulated. If humidity has a measurable effect on the gas
readings, the temperature tests are performed at constant relative
humidity (not absolute humidity). Any temperature corrections should
be multiplied by any humidity corrections to obtain true readings.

7. Storage Life. Samples of tubes are stored for extended periods to

evaluate their accuracy at dened time periods to determine their

storage life. The user should store tubes in darkness at 3° to 7°C (37°
to 45°F) to maximize their shelf life. Freezing tubes (storage below
0°C, or 32°F) can damage some types and is not recommended.

8. Cross-Sensitivity. Tubes are challenged with a variety of possible

interfering gases to quantitate their relative response. Although the
tubes are highly selective, compounds that are chemically similar to
a target compound sometimes show a positive interference. Others
interfere with the measurement gas without showing a response
on their own; for example, when acidic vapors coexist with basic
vapors. Such information is listed in a separate note or column titled
“Interferes in Mixtures.” The user should know as much about the
sample environment as possible in order to make sound judgments
regarding possible interferences; otherwise inaccurate readings may
result. In some cases, a different color or pattern of the stain can clue
the user to the presence of an interfering compound.

TECHNICAL INFORMATION

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4.3 Humidity, Temperature, Pressure, and Matrix Effects

1. Humidity

Humidity has little effect on most tubes either because the reaction is
insensitive to moisture or because drying agents are added to absorb
the moisture in a pre-layer (see Figure 4-2). Humidity tends to have
the greatest effect on compounds that are highly water-soluble, such

as acids and bases. HF (hydrouoric acid) is a notable example that

requires humidity corrections; water-adsorbing prelayers cannot be
used because they tend to be reactive with HF. The humidity effect
tends to be greater as the concentration range of the tube is lowered.
When correcting for humidity, the CF is multiplied by the reading in
addition to multiplying by any temperature correction. Any necessary

TECHNICAL INFORMATION

Correction Factors are listed in the individual tube data sheets. Note

that the relative humidity at the measurement temperature denes the

correction, rather than the absolute humidity.

Figure 4-2. Effect of humidity on gas detection tube readings.

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2. Temperature

Temperature can affect gas tube readings in at least three ways. First,
as the temperature increases, the gas density decreases, causing a
tendency for the reading to decrease (see pressure effects described in
the next section). Second, as the temperature increases, the reaction
rate increases, causing the reading to be sharper and shorter. A third,
balancing effect is that adsorption is often a prerequisite for reaction.
Adsorption is weaker as temperature increases, and thus the reading
can become longer. The interplay of these competing effects results in
some stains that are longer with increasing temperature, and others
that are shorter.

TECHNICAL INFORMATION

Figure 4-3. Effect of temperature on gas detection tube readings.

Additional factors occur in special cases. For example, pretube or prelayer
reactions are sometimes more complete at higher temperatures,
causing higher readings in the measurement layer. In some cases, the
color of the stain can change. In the water vapor H-10-120-20 tube,
the color stain is green at room temperature and a more purple color
below room temperature.

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3. Pressure

TECHNICAL INFORMATION

Tubes change color in proportion to the mass of the compounds
reaching the reagent (i.e, the absolute concentration). Therefore, as
the pressure decreases at higher altitudes, the apparent response is
reduced because there are fewer molecules per unit volume sampled.
The conventional desired reading is in ppmv (parts per million by
volume), which is a relative concentration, such as a mole or volume
fraction (% of molecules of compound per molecules of total gas [air]),
rather than an absolute concentration.

All Honeywell tubes are calibrated at 1 atmosphere (760 mm Hg)
pressure at sea level.

• For tubes calibrated in absolute concentrations such as lbs./MMCF or
mg/m3, no pressure corrections are needed.

• For tubes calibrated in relative concentrations (e.g., ppm), correct for
pressure using one of the following equations:

Corrected reading = Observed Reading x 760 mm Hg
Pressure (mm Hg)

Corrected reading = Observed Reading x 101.3 kPa
Pressure (kPa)

Corrected reading = Observed Reading x 14.7 psia
Pressure (psia)

The pressure in mm Hg can be estimated as a function of altitude using
the following equation:

P (mm Hg) = 760exp(-0.1286[alt(km)]) below 2 km

Example Correction Factors are listed in the following table as a
function of altitude. Weather changes may also affect the atmospheric
pressure, but the necessary corrections are usually <10%.

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Example Location Altitude

(km)

Altitude

(feet)

Pressure,

(mm Hg)

CF

San Francisco, CA 0 0 760 1.00
Atlanta, GA 0.3 1000 731 1.04
Spokane, WA 0.6 2000 703 1.08
Rapid City, SD 0.9 3000 676 1.12
Salt Lake City, UT 1.2 4000 650 1.17
Denver, CO 1.5 5000 625 1.22
Colo. Spgs., CO 1.8 6000 601 1.27
Santa Fe, NM 2.1 7000 578 1.32
Alta, UT 2.4 8000 555 1.37
Winter Park, CO 2.7 9000 534 1.42
Keystone, CO 3.0 10000 514 1.48

4. Matrix Gas

The matrix gas usually has little or no effect on the tube readings as long
as the gas does not chemically react with the tube reagents or measured
compound. Thus, readings in air, nitrogen, hydrogen, helium, or carbon
dioxide give essentially the same results. However, the viscosity of the

gas has a signicant effect on the sampling time. Thus, for example, the

sampling time of the CO H-10-102-18 tube is about half as long in pure

hydrogen (viscosity 9.0 μPa-s) as it is in air (viscosity 18.6 μPa-s).

TECHNICAL INFORMATION

Viscosity

Matrix Gas

Air 18.6 1.00 90
n-Butane 7.5 0.40 36
Propane 8.3 0.45 40
Hydrogen 9.0 0.48 44
Ethane 9.5 0.51 46
Acetylene 10.4 0.56 50
Methane 11.2 0.60 54
Carbon Dioxide 15.0 0.81 73
Nitrogen 17.9 0.96 87
Helium 20.0 1.08 97
Oxygen 20.8 1.12 101
Argon 22.9 1.23 111
Neon 32.1 1.73 155

@ 27°C

(μPa-s)

Sampling Time

Relative to Air

Sampling Time for

a 90 second Tube

(seconds)

At a given viscosity, higher ow rates tend to give longer stains. However,

this is often compensated by higher diffusion rates to the reactive surface

in the less viscous gases, resulting in no signicant effect on the readings.

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5. DATA SHEETS FOR GAS DETECTION TUBES

Acetone C3H6O No. H-10-111-40

Extended

Range

Standard

Range
Range (ppmv) 0.05 - 1% 0.1 - 2% 0.2 - 4%
No. of Pump Strokes 2 1 0.5
Sample Volume (mL) 200 100 50
Sample Time (min) 2 x 2 2 1.5
Correction Factor 0.5 1 2

Precision (Relative Standard Deviation)*: ≤ ±12%

2

Linearity with No. of Pump Strokes: r

= 0.992

Humidity: No effect 5 - 85% RH

Temperature Range: 0 - 40°C (32 - 104°F)

Temp (°C/°F) 0/32 10/50 25/77 40/104
Corr. Factor 1.25 1.15 1.0 0.95

Storage Life: 2 years in darkness at 5 - 25°C (40 - 77°F). Refrigeration preferred.

Color Change: Orange → Black

Reaction Principle: CH

DATA SHEETS

Cross-sensitivity:

Substance
Methyl ethyl ketone 0.6% 0.55% 1.1

Methyl propyl ketone
Methyl isobutyl ketone
CO
CO

2

CH

4

NH

3

S

H

2

Ethyl Acetate
Hexane
Isobutylene
Toluene

* Data based on Honeywell pumps and tubes used in standard range.

#

Faint black color over entire stain length. Ketones can be distinguished by their

darker stains and sharp endpoints.

COCH3 + Cr(VI) + H2SO4 → Cr(III) + Oxidation Prods.

3

Concentration

(ppmv)

1.0% 0.65% 1.5

1.0% 0.40% 2.5

1.5% 0 -

1.5% 0 -

2.5% 0 -

5.0% 1.4% brown 3.6
300 0.5% diffuse

1.0% 0.85% diffuse

0.24% entire tube

0.20% entire tube
400 0.3% diffuse

Apparent
Reading*

#

#

#

#

#

Extended

Range

Corr.

Factor

-

-

-

-

-

Other Possible Interferences: Other hydrocarbons.

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Amines RNH

(CH

2

NH

3

) No. H-10-132-10

2

Extended

Range

Range (ppmv) 0.25 - 5 0.5 - 10 1.0 - 20
No. of Pump Strokes 2 1 0.5
Sample Volume (mL) 200 100 50
Sample Time (min) 2 x 1 1 1
Correction Factor 0.5 1.0 2.0

Standard

Range

Extended

Range

Precision (Relative Standard Deviation)*: ≤ ±20%
Linearity with No. of Pump Strokes: r

2

= 0.997

Humidity: No effect 0 - 90% RH

Temperature Range: 0 - 40°C (32 - 104°F) @ constant 50%RH.

Temp (°C/°F) 0/32 10/50 20/68 30/86 40/104
Corr. Factor 1.16 1.10 1.0 0.96 0.96

Storage Life: 1 year in darkness at 5-25°C (40-77°F). Refrigeration preferred.
Color Change: Pink → Yellow
Reaction Principle: 2RNH

Cross-sensitivity:
Substance

Ammonia 5 6.0 0.8
Methylamine 10 10* 1.0
Ethylamine 8 7.0 1.1
Allyamine 7.4 8.0 0.93
Diethylamine 5 6.3 0.79
Trimethylamine 4.5 9.8 0.46
Triethylamine 6 9.5 0.63
Methylaziridine (Propylene imine) 5 6.5 0.77
Ethylenediamine 7 2.0
Ethanolamine 36 4.1
Pyridine 10 Over range
H2S 100 0
CO 500 0
Isobutylene 100 0
HCl 1000 0

* Data based on Honeywell pump and tubes used in standard range. This tube is
calibrated using methylamine.

#

Deep purple with yellow stain at endpoint.

†

Slight color change to light pink.

£ Interferes in mixtures.

+ H2SO4 → (RNH3)2SO4

2

Concentration

(ppmv)

Apparent
Reading*

#

#

£

†

Correction

Factor

3.5

8.8

-

Other Possible Interferences: Other bases.

DATA SHEETS

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Ammonia NH3 No. H-10-100-05

Extended

Range

Range (ppmv) 0.5 - 15
No. of Pump Strokes
Sample Volume (mL)
Sample Time (min)
Correction Factor

2 1 0.5

200 100 50

2 x 1.5 1.5 1

0.55 1 2.4

Standard

Range

1 - 30

Precision (Relative Standard Deviation)*: ≤ ± 12%

Linearity with No. of Pump Strokes: r

2

= 0.999

Humidity: The tubes are calibrated at 50% RH @ 24 °C (75 °F)

% RH < 5% 10% 50% 80% 95%

Corr. Factor 0.8 0.85 1.0 1.0 1.0

Temperature Range: 0 - 40°C (32 - 104°F) @ constant 50%RH

Temp (°C/°F) 0/32 10/50 25/77 35/95
Corr. Factor 0.9 0.95 1.0 1.1

Storage Life: 2 years in darkness at 5 - 25°C (40-77°F). Refrigeration preferred.
Color Change: Purple → Beige
Reaction Principle: Prelayer reduces humidity effects

3NH

+ H3PO4 → (NH4)3PO4

DATA SHEETS

Cross-sensitivity:
Substance

3

Concentration

(ppmv)

Apparent
Reading*

Pyridine 10 15
Diethylamine
Hydrazine
Methylhydrazine
CO
CO

2

H2S
Hexane
Isobutylene
Toluene

* Data based on Honeywell pumps and tubes used in standard range.
** These hydrazines can be measured using 2 strokes with a CF of 5.

#

16000 ppm CO2 reduces the NH3 response by 30% in mixtures, 5000 ppm CO2 reduces

NH

response by 10% in mixtures, and 1000 ppm CO2 has no effect.

3

20 18
20 2**
20 2.3**

100 0

20000 0#

200 0
100 0
100 0
100 0

Other Possible Interferences: Amines and other bases.

Extended

Range

2 – 60

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