Hukseflux HF03 / LI19 User Manual

HF03 / LI19

PORTABLE HEAT FLUX SENSOR,

WITH READ-OUT UNIT

USER MANUAL

HF03 / LI19 manual v1215

Edited & Copyright by:

Hukseflux Thermal Sensors
http://www.hukseflux.com
e-mail: [e-mail]

H u k s e f l u x T h e r m a l S e n s o r s

Warnings and safety issues:

HF03 / LI19 is NOT certified for EEx
environments.

HF03 is designed for fluxes up to 10
kW/m2. LI19 is suitable for normal
exposure only; up to 2 kW/m2.

Make sure that LI19 is switched off
whenever it is not used.

Make sure to have spare batteries
available whenever using LI19.

Make sure to have read the LI19
manual before using LI19.

LI19 software is not supplied with the
instrument. It should be downloaded
from

http://www.leiderdorpinstruments.nl

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Contents

List of symbols 4
Introduction 5

1 Specifications of HF03 / LI19 7
2 General Theory 8
3 Short user guide 9
4 Putting HF03 / LI19 into use 12
5 Maintenance of HF03 13
6 Electrical connection of HF03 14
7 Appendices 15

7.1 Appendix on trouble shooting 15

7.2 Allowable levels 16

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List of symbols

Heat flux  W m-2
Voltage output V
HF03 sensitivity E

V

sen

V/Wm-2

sen

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Introduction

The HF03 is a heat flux sensor that can be used in mobile
applications. It is combined with LI19, a high accuracy hand-held
read-out unit that can be used both for mobile measurements
and as an amplifier directly connected to a PC.
The combination HF03 / LI19 is typically used to study heat flux
levels around flares and fires, and to calibrate flare radiation
monitors / flare heat flux sensors.

The HF03 is a heat flux sensor of the type that is commonly used
in fire testing. The HF03 housing and sensor are designed to be
suitable for short (10 minute) observation of high flux
environments (up to 10 kW/m2). LI19 is suitable for normal
exposure only; up to 2 kW/m2.

LI19 is used to display the measured flux level; for attaining
that, the sensitivity of HF03 is entered into the LI19, by
programming it using a PC. USB connection is part of the
delivery. Software should be downloaded via internet (this is to
ensure that the latest version is applied). The applied site is:
http://www.leiderdorpinstruments.nl.
The LI19 is battery powered, using 2 AA-type batteries. These
are included in the delivery.
Batteries allow 50 days of operation.

HF03 / LI19 is not rated for EEx environments, nevertheless it is
admitted in many cases, because the instrument operates on
3VDC only.

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10

9

8

11

LI -1 9

kW /m

2

5 0 .0

1 2

3

4

6 5

Figure 0.1 LI19 connected to HF03. Heat flux sensor surface

(11), metal heat sink (10), plastic grip (9), polyurethane cable
(7).

Operation:
1 switch on LI19, connect HF03
2 connect LI19 to PC, using USB connection box and LI19
software
3 check sensor settings
4 disconnect from PC
5 optional: mark settings on LI19
6 remove HF03 cap
7 start measurement
8 switch off LI19

Delivery:
HF03 / LI19 / 2 spare batteries / Transport casing / USB
connection box / cap HF03. Software should be downloaded from
http://www.leiderdorpinstruments.nl

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HF03 / LI19 GENERAL SPECIFICATIONS

Heat flux range for
HF03:

up to 10 kW/m2

Exposure time for
HF03:

10 minutes (max)

Heat flux range for
LI19:

up to 2 kW/m2

Exposure time for
LI19:

indefinite
Cable length:

5 m

response time

1 s (nominal value)

Temperature range

-30 to +80 °C

A/D resolution:

1 or 10 µV or 0.1 kW/m2

Software

To be downloaded from
http://www.leiderdorpinstruments.nl

Display functions:

actual values

Weight:

LI19 plus HF03: 1 kg
Including transport casing: 2.5 kg
Transport casing dimensions:
30 x 40 x 12 cm approximately

power supply:

Two AA-Type batteries, Alkaline

Transport casing

supplied with the instrument

Sensor sensitivity

0.1 mV/kW/m2
At 1000 W/m2: 100 μV
At 100 kW/m2: 10 mV

Sensor field of view

Around 180 degrees

Sensor protection

Removable cap

CALIBRATION

Calibration
traceability

NIST
Recalibration interval

Every 2 years

1 Specifications of HF03 / LI19

The HF03 is a heat flux sensor that can be used in mobile
applications. It is combined with LI19, a high accuracy hand-held
read-out unit that can be used both for mobile measurements
and as an amplifier directly connected to a PC. It is supplied with
a transport case.

Table 1.1 List of HF03 / LI19 specifications

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2 General Theory

The HF03’s main component is a heat flux sensor. The sensor is

located under the black surface on the front of the HF03. It is
mounted on a metal heat sink, which is in turn protected by a
plastic housing. The heat flux sensor generates a small voltage
signal that is a linear function of the incoming radiant and
convective heat flux.
Using HF03 is easy. For readout, one only needs an accurate
voltmeter that works in the millivolt range. To convert the
measured voltage V
divided by the sensitivity E
each individual sensor.

 = V

sen

/ E

2.1

sen

The sensitivity of HF03 is supplied with each individual
instrument, and can be found on its calibration certificate.

HF03 is read-out by LI19, which essentially is a voltmeter in
which a calibration factor can be entered, to show watt per meter
square.

Expected accuracy:

The expected accuracy of a measurement with HF03 depends on
many factors, but most of all on:
1 the intensity of the radiation
2 wind effects

HF03 is calibrated with a radiant source under conditions of
“natural convection” i.e. no wind.
The wind can play a large role in determining the end result of
the heat flux measurement, and also in discrepancies between
measurement results of one sensor type and another because
surface temperatures on different sensors will deviate from each
other. The quantification of this effect is strongly dependent on
the circumstances. However, deviations of up to 20% have been
reported for different sensor designs, although these were
calibrated under the same conditions.

to a heat flux , the voltage must be

sen

, a constant that is supplied with

sen

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3 Short user guide

0 unpack

0.1 in case this is not done before: download software from

http://www.leiderdorpinstruments.nl (products – LI19 – more –

downloads)

0.2 in case this was not done before: take the plastic units strip
and cut off the units that are required. The small strip can be
placed on the LI19 front below that display.

1 switch on LI19, connect HF03
2 connect LI19 to PC, using USB connection box and LI19
software
3 check sensor settings
4 disconnect from PC
5 optional: mark settings on LI19
6 remove HF03 cap
7 start measurement
8 switch off LI19

Figure 3.1 LI19 screen at startup.

Typically the front of the LI19 should have the sensor
information copied (possibly on a sticker).

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Figure 3.2 LI19 connected to the USB connection box.

Installation of the LI19 program will typically be done
automatically by the windows installer. In case older program
versions are present, one might need to uninstall earlier
versions.

If the LI19 program is opened, the LI19 must be connected,
using the USB connection box.
The control untilities will automatically recognise the LI19, and
the window as shown in figure 3.3 will open, giving the message
that the unit is connected.

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Figure 3.3. LI19 software screen.

Press sensor settings:

Figure 3.4 LI19 sensor settings screen.

Press Select Sensor, and select HF03. Select the appropriate
calibration figure for the HF03 that is used. This will be around
95, resulting in a multiplier of 2000 and a divider of around

1900. The LI19 is now ready for use. It is suggested to make a
sticker on the LI19, stating that the calibration is 95.

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Remove cap on the HF03 so that the
black surface of HF03 shows up.

Switch LI19 on. The on/off button is
located on top of the LI19. It needs to
be pressed, to reach a level below the
plastic surface to remain on.

Connect LI19 to a PC, using the USB
connection block. Make contact
through the LI19 software.

The program does not
connect to the LI19 if
the LI19 is switched off.

Check the sensor settings in the LI19
software against the HF03 calibration
value (see HF03 certificate and sticker
on the sensor). Disconnect the USB
connection block and the PC.

LI9 is now ready for use
Connect the HF03. + wire is white. The
white wire should be connected to the
red plug, the black wire to the black
plug.

HF03 / LI19 is now
ready for use.

Darken the sensor for instance by
putting the sensor upside down on a
table. The reading should be anywhere
between +50 and -50 W/m2. (reading
proportional to temperature difference
table-sensor, with 50 W/m2 around 10
degrees difference)

Check if the sensor reacts to heat flux.
Expose the sensor to radiation of lamp
on desk or to solar radiation.
Preferably in indoor environment. (no
wind). The reading should reach a
stable value. (direct solar beam
radiation is typically 700 W/m2 on a
clear day; direct plus diffuse max 1300
W/m2, lamp radiation at a level that
feels warm with the hand: around
1000 W/m2)

The thermopile should
react by generating a
millivolt output signal.

4 Putting HF03 / LI19 into use

It is recommended to test if the sensor works, according to the
following table: (estimated time needed: 5 minutes)

Table 4.1 Checking the functionality of the sensor. The procedure

offers a simple test to get a better feeling how HF03 / LI19
works, and a check if the sensor is OK.

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5 Maintenance of HF03

HF03 and LI19 are virtually maintenance free.
In case this is necessary, HF03 can be cleaned with water or mild
alcohol.
LI19 consumes power. Batteries must be replaced on a regular
basis.
At regular intervals the quality of the cables can be checked.

On a 2 yearly interval the calibration can be checked in an indoor
facility.

Figure 5.1 Battery replacement of LI19.

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Wire

Colour

Measurement
system LI19

Sensor output +

White

Red connector

Sensor output -

Black

Black connector

Shield

steel

Not conected

6 Electrical connection of HF03

Table 6.1 The electrical connection of HF03 to LI19.

Figure 6.1 Connectors on LI19, and on/off switch.

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The sensor
does not give
any signal

1 check functionality according to table 4.1.
2 if the sensor does not work: measure sensor
impedance across the black and white wires,
using a multimeter, in a situation that the sensor
is not exposed to radiation. The value should not
be zero; this indicated a broken circuit. The value
also should not read infinite. Report the
resistance value back to Hukseflux.
2 Check if the sensor reacts to an enforced heat
flux. A 100 Watt lamp mounted at 10 cm distance
should give a definite reaction.
3 Check the data acquisition: apply a mV source
to the LI19 in the 1 mV range.

The sensor
signal is un­realistically
high or low.

1 Check if the right calibration factor is entered
into the algorithm. Please note that each sensor
has its own individual calibration factor.
2 Check the condition of the leads at the logger.
3 Check the cabling condition looking for cable
breaks.
4 Check the data acquisition by applying a mV
source to it in the 1 mV range.

The sensor
signal shows
unexpected
variations

1 Check the presence of strong sources of
electromagnetic radiation (radar, radio etc.)
2 Check the condition of the sensor cable.

7 Appendices

7.1 Appendix on troubleshooting

This paragraph contains information that can be used to make a
diagnosis whenever the sensor does not function.

Table 7.1.1 Troubleshooting for HF03 / LI19

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Btu/Hr Ft2

kW/m2

Equipment

3000

9.5

Human: Run

2000

6.3

Human: Walk

1500

4.7

Human: Work
(static)

500

1.6

7.2 Allowable levels

An indication of allowable heat flux levels for personel and
equipment can be found below.

Figure 7.2.1 Allowable heat flux levels

7.3 Datalogging

LI19 can also be used as a datalogger. In case you need this
capability, the LI19 manual can be obtained from

http://www.leiderdorpinstruments.nl.

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