Test of Toy Balloons Performed For Federal Department of Aviation

Project no. 25307 - 1 June 1992
Report No. 78-0137 / 00052
Attachment to 92-08440


CONTENTS

  1. IDENTIFICATION
  2. BACKGROUND
  3. GENERAL
    1. Introduction
    2. Test Specimen
    3. Test Equipment
  4. TEST AND RESULTS
    1. Procedure
    2. Results
  5. CONCLUSION
  6. APPENDIX: Curve for converting between pressure and height


IDENTIFICATION

    Project no.     : 25307
    Title           : Test of toy balloons performed for Federal Department of Aviation
    Rekvirent       : Statens Lufthavensvaesen
                      Box 744
                      Ellebjergvej 50
                      2450 Copenhagen SV, Denmark

                      Phone 011 45 36 44 48 48
    Reference       : Hr. Kofoed-Hansen
    Test Specimen   : 10 pcs. latex balloons (11 inch Qualatex)
                      10 pcs. mylar balloons (18 inch Anagram)
    Test Period     : 1992.April.23 - 1992.April.24
    Testing done by : Tom Hjerting Nielsen
                      Susanne Otto
    Signature       : Original Signed by Susanne Otto

BACKGROUND

The Federal Department of Aviation has until now had the understanding that toy balloons attain a maximum height of a couple of hundred meters, but have now received information that indicates that they can go much higher and with that become a larger danger for air traffic than previously considered.

Therefore, testing is performed with the purpose of determining the height at which balloons explode. The height is determined with the help of a vacuum chamber.

GENERAL

Introduction

At Electronic Central, tests were performed on toy balloons for the Federal Department of Aviation. The purpose of the tests was to determine the height at which balloons explode.

The tests were performed in a vacuum chamber, where the pressure was slowly reduced and the temperature was reduced simultaneously. Notes were made at which pressure the balloons exploded. The pressure can be converted to an equivalent height.

The tests were performed on two types of toy balloons: 18" mylar and 11" latex.

Test Specimens

As received from CHA CHA Balloon Company, Allerod, 1992.April.23:

10 pcs. latex balloons, 11" diameter (Qualatex)
10 pcs. mylar balloons, 18" diameter (Anagram)

The balloons were delivered, filled with 14 liters of helium.

Test Equipment

Thermal vacuum chamber: EC type TVK-2K, EC no. U2401
Date of last calibration: not relevant

U-tube manometer: EC no. 23996
Date of last calibration: not relevant

Normal pressure was checked several times during testing according to EC no. 23742 (Aneroid Barometer)

TEST AND RESULTS

This chapter describes the tests performed with consideration of the procedure and results.

Procedure

The tests were performed according to the following procedures.

Five balloons at a time were installed in the vacuum chamber. The pressure in the chamber was gradually reduced. The temperature in the chamber was reduced to -20*C. The pressure at which each balloon explodes is noted together with eventual comments. When all balloons have exploded the temperature and pressure in the chamber are increased to standard laboratory conditions.

First the ten latex balloons were tested and then the 10 mylar balloons were tested.

Results

The test was carried out as described. Fig 1 and 2 show the test specimens in the vacuum chamber.

(The figure has been eliminated due to the poor quality of my copy - Don Gebhard)

FIG. 1 Latex balloons in vacuum chamber. (on page 6 of original report)

(The figure has been eliminated due to the poor quality of my copy - Don Gebhard)

FIG. 2 Mylar balloons in vacuum chamber. (on page 7 of original report)

The Table on the next page shows the pressure and the equivalent height at which each balloon exploded. The height was found with linear interpolation of values from IEC 68-2-13 and with that ISO standard 2533 (see appendix 1).

Pressure And Equivalent Height At Which Balloons Exploded
Balloon Type Temperature
°C
Pressure
mm Hg
Height
meters
Notes
         
Latex -20.9 228 9200  
Latex -20.9 220 9450  
Latex -20.9 220 9450  
Latex -20.9 216 9600  
Latex -20.9 204 9900  
 
Latex -20.6 203 9900  
Latex -19.4 193 10250  
Latex -19.7 189 10400  
Latex -21.9 180 10650  
Latex -20.9 179 10650  
 
Mylar 13.8 677 400  
Mylar -6.0 644 1000 1
Mylar -6.0 644 1000 1
Mylar -20.6 582 2000 1
Mylar -20.3 549 2600 1
 
Mylar -21.7 559 2400 2
Mylar -20.5 549 2600 1
Mylar -20.5 499 3450  
Mylar -21.1 426 4650  

Notes:

  1. One balloon sank down to the bottom of the vacuum chamber.

  2. Two balloons sank down to the bottom of the vacuum chamber.

CONCLUSION

The results of the finished tests can conclude the following:

Latex balloons explode with in the area of 9200 - 10650 meters altitude with a middle value of 9945 meters altitude. In general, the balloons used in the second test exploded at a higher altitude that the balloons used in the first test. This can be attributed to helium loss during the waiting time having resulted in a reduced internal pressure.

The mylar balloons do not go higher than 1000 - 2400 meters before they either explode or lose their "lift." It is noted that there was a wide range in results for the mylar balloons.

APPENDIX

Curve for converting pressure and height

Altitude vs Pressure
IEC 68-213 (ISO 2533)

Pressure
(mbar)

 20
100
200
300
400
500
600
700

   0        5000        10000        15000       20000        25000        30000        35000

                                            Altitude (meter)