ICS 43 040.60  
T 26 
 
 
National Standard for the People’s Republic of China  
GB 11555-200× 
In replacement of GB11555 -1994  
GB11556 -1994  
 
 
 
 
Motor vehicle s - windshield demisting and defrosting systems   
Performance requirements and test methods  
 
(Draft for App roval)  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Released on ××/××/20 ××                                   Implemented on ×× /××/20 ×× 
Issued by  
 
General Administration of Quality Supervision,  
Inspection and Quarantine of the People’s Republic of China  
Standardization Administration  of the People’s Republic of China  GB 11555 -200× 
Table of contents  
 
Introduction ................................ ................................ ................................ ................................ ...... 3 
1. Scope ................................ ................................ ................................ ................................ ........ 5 
2. Reference guidelines ................................ ................................ ................................ ................. 5 
3. Terminology and definition ................................ ................................ ................................ ....... 5 
4. Determine A, B and A area ................................ ................................ ................................ ........ 7 
5. Requirements ................................ ................................ ................................ ........................... 9 
5.1. Defrosting requirements for windshield ................................ ................................ ................ 9 
5.2. Demisting requirements f or windshield ................................ ................................ ................ 9 
6. Test method ................................ ................................ ................................ ........................... 10 
6.1. Windshield defrosting test method ................................ ................................ ..................... 10 
6.1.1.  Test conditions ................................ ................................ ................................ ............... 10 
6.1.2.  Test instrument, device and requirements ................................ ................................ ...... 11 
6.1.3.  Test procedure ................................ ................................ ................................ ............... 11 
6.2. Windshield demisting test method ................................ ................................ ..................... 11 
6.2.1.  Test conditions ................................ ................................ ................................ ............... 11 
6.2.2.  Test  instrument, device and requirements ................................ ................................ ...... 12 
6.2.3.  Test procedures ................................ ................................ ................................ .............. 13 
Appendix A (Reference Appendix) The correlation of the chapter  numbering in this standard and 
78/317/EEC ................................ ................................ ................................ ................................ .....14   GB 11555 -200× 
 
Introduction  
 
The Technical contents of this standard  are mandatory.  
This standard has adopted EU 78/317/EEC (21/12/1977) OJ NO. L81 (28/03/1978) “ Council 
Directive  on the appr oximation of the laws of the Member States relating to the defrosting 
and demisting systems of glazed surfaces of motor vehicles ” (English version).  
This standard replaces GB11555 -1994  “Motor vehicle windshield demisting system 
performance requirements and  test methods” and GB11556 -1994 “Motor vehicle windshield 
defrosting system performance requirements and test methods”.  
This standard as been re -drafted as per 78/317/EEC. Appendix A has listed the correlation on 
the chapter and section numbering between  this standard and that in the 78/317/EEC.  
The following amendments have been made in this standard according to the actual situations 
in China when adopting the 78/317/EEC directive.  
The differences and their reasons between this standard and the 78/317/EEC  directive are as 
follows:  
— Content regarding certification has been removed from 78/317/EEC directive (i.e. 
chapter 3, 4 of Appendix 1 and Appendix 6) . This is due to the difference in format 
between standard and directive.  
— The following have been removed from the 78/317/EEC directive Appendix 1: “2.3 
three -dimensional system of coordinate” , “2.4 basic reference marking”, “2.5 seat 
backrest angle”,  “2.6 actual seat backrest angle”, the definition of “seat backrest 
angle design” ; Appendix 2 : “determining th e H point and the actual seat backrest 
angle, verification of the relative location between point R and H, and the verification 
procedures for the correlation between seat backrest angle design and actual seat 
backrest angle” ; Appendix 3 : “the correlation between vehicle basic reference 
marking and the three -dime nsional system of coordinate”. Those contents have 
already been covered in the GB 11551 -2003 and GB11562 -1994 and are consisten t. 
For ease of use, the following have been amended to the 78/317/EEC d irective in this 
standard:  
— “This directive” has been changed to “this standard”;  
— “Definition” has been changed to “terminology and definition”;  
— Reference Appendix A has been added.  
The main differences between this standard and GB11555 -1994 and GB11556 -1994: 
— “180° range of vision for the driver” (1 in this edition) has been added;  
— Definitions for “V point”, “R point” (3.8 and 3.9 in this edition) has been added;  
— “Defrosting device” has been changed to “defrosting system” (3.1 in this edition).  
“Defrosting device” has been changed to “defrosting system” (3.4 in this edition).  
— “The dimension and the features of vapour generator” (6.2.2.1 d in this edition) has 
been added;    GB 11555 -200× 
— “Within 5 minutes  from the start of the test, programmed “fast idle speed” can be used 
(recommended by manufacturers for cold weather engine start)” and “ Voltage on the 
terminals of the defrosting system should be no more than 20% of the system’s rated 
voltage” (6.1.1.5 and 6.1.1.9 in this edition) ha ve been added.  
 
Appendix A is for refere nce. 
This standard is brought forward by the National Development and Reform Commission.  
This standard is administered by the National Automotive Standardization Technical 
Committee.  
Drafted by: Wuhan  Auto  Parts Research Institute , Dong Feng Automotive  Eng ineering 
Research Academe , National Quality Certification Centre.  
Drafted by: LI Zaihua, YU Boying, QU Yanping.  
This standard was first release in 1994. This is the first revision.    GB 11555 -200× 
 
Motor vehicles - windshield demisting and defrosting systems  
Performance requirements and test methods  
1. Scope  
This standard specifies motor vehicle windshield demisting and defrosting systems 
performance requirements and test methods.  
This standard is applicable to 180° range of vision for the driver for M1 vehicles.   
2. Reference guidelines  
When quoted in this standard, the terms in the following documents become standard 
terms. Any quoted documents with dates, and all its su bsequent amendments to a single  (not 
includi ng the contents of corrigenda) or revised edition, are not appli cable to this standard. 
However, relevant parties who reach an agreement according to the standard are encouraged 
to research into whether the latest versions of these documents should be used. For 
documents without a quoted date, the latest version applie s to this standard.  
GB 11551 -2003 Passenger protection for frontal collision  (NEQ ECE R94 1995)  
GB 11562 -1994 Requirements and measurement methods of frontal range of vision for 
the driver  (EQV 77/649/EEC:1977)  
3. Terminology and definition   
The followings are applicable to this standard  
3.1.  
Defrosting system  
The system that thaws the frost or ice on the windshield so that vision is resumed.   
3.2.  
Defrosting  
Remove the frost or ice on the windshield through defrosting or the operation of the 
windscreen wiper.   
3.3.  
Defrosted area  
The area of the windshield that is dry or completely or partially thawed and covered by 
damp frost. The frost can be cleared by windscreen wiper from the outside. This does not 
include the area that is covered by dry frost.    GB 11555 -200× 
3.4.  
Demisting system   
Use to clear the cold condensation from the windshield so that normal vision is  possible .  GB 11555 -200× 
 
3.5.  
Mist  
The condensation on the windshield.   
3.6.  
Demisting  
Removal of mist from the windshield by demisting system.  
3.7.  
Demisted area  
The area on the windshield where t he normal vision is possible after demisting.  
3.8.  
V points  
V point is the point indicating driver’s eye position. It’s determined by the driver’s 
seating position ( if the seat is adjustable, move the seat to furthest back) , R point and seat 
backrest angle d esign  (see GB11562 -1994 3.4.1). V point is used to check if the range of 
vision meets the requirement. V1 and V2  points  are usually used to indicate the different 
positions of V  point (see Figure 1) . 
3.9.  
R points  
“R point”  is “seating reference point ”. Its definition is as per GB 11551 -2003  3.7.  
4. Determine A, B and A area   
4.1. A area is the enclosed area formed from where the 4 planes extended from V point 
(i.e. V1 and V2, see GB 11562 -1994 3.5.1; To determine the V point, see GB 11562 -
1994 5.1) meeting the winds hield  (see Figure 1) .  
4.1.1.  The vertical plane 13°to the left of the X axis which passes V1 and V2  
point . 
4.1.2.  The plane which forms a 3°elevation  to the X axis, passes V1 point and is 
parallel to Y axis.     GB 11555 -200× 
4.1.3.  The plane which forms a 1°angle of depression to the X axis,  passes V2 
point and is parallel to Y axis.  
4.1.4.  The vertical plane 20°to the right of the X axis which passes V1 and V2 
point.  
 
(1) Track of the longitudinal centre plane of the vehicle;  
(2) Track of the vertical plane that passes the R point;  
(3) Track of th e vertical plane that passes the V1 and V2 points.  
 
Figure 1 A area  
 
4.2. B area is the area on the windshield outer surface enclosed by the following 4 
planes. In addition, it should be at least 25mm inside the edge of the windshield, 
whichever is smaller  (see Figure 2) . 
4.2.1.  The plane which forms a 7°elevation to the X axis, passes V1 point and is 
parallel to the Y axis.  
4.2.2.  The plane which forms a 5°angle of depression to the X axis, passes V2 
point and is parallel to the Y axis.  
4.2.3.  The vertical plane 17°to the left of t he X axis which passes V1 and V2 
points.  
4.2.4.  Based on the longitudinal centre plane of the vehicle and symmetrical to 
the plane described in 4.2.3.   
4.3. A area is based on the longitudinal centre plane of the vehicle and symmetrical to 
the A area .  
   GB 11555 -200× 
 
 
 
(1) Track  of the longitudinal centre plane of the vehicle;  
(2) Track of the vertical plane that passes the R point;  
(3) Track of the vertical plane that passes the V1 and V2 points.  
 
Figure 2  B area  
 
5. Requirements  
 
5.1. Defrosting requirements for windshield  
5.1.1.  Every vehicl e should be equipped with a defrosting system. This is to 
ensure  that visibility  can be resumed in cold weather conditions.  
5.1.2.  The following requirements should be met:   
5.1.2.1.  20 minutes  after beginning  the test, 80% of A area should have been 
defrosted;  
5.1.2.2.  25 minute s after  beginning  the test, 80% of A area should have been 
defrosted;  
5.1.2.3.  40 minutes  after beginning  the test, 95% of B area should have been 
defrosted.  
5.2. Demisting requirements for windshield  
5.2.1.  Every vehicle should be equipped with a demisting system. This is to 
ensure that visibility is possible in wet weather conditions.  
5.2.2.  The following requirements should be met:   
5.2.2.1.  10 minutes  after beginning  the test, 90% of A area should have been 
demisted;  
5.2.2.2.  10 minutes  after beginning  the test, 80% of B area should have been 
demi sted;    GB 11555 -200× 
 
6. Test method  
 
6.1. Windshield defrosting  test method  
6.1.1.  Test conditions  
6.1.1.1.  Test is conducted under the temperature of -18°C±3°C. See Figure 3 
for measuring point s.  
 
Note: “O” point is on the longitudinal centre plane of the vehicle  300mm in front of the 
wind shield bottom edge.  
Figure 3 Test temperature and wind speed measuring point  (“O” is the measuring point ) 
 
6.1.1.2.  Test should be conducted in a low temperature that can accommodate 
the vehicle. The room should be equipped with a cold air circulation device. 
Circu late the cold air. The room should be maintained at the temperature 
specified in 6.1.1.1 for at least 24 hours before the test vehicle is placed in 
the room.   
6.1.1.3.  Before the test, clean any smears on both the inside and outside of the 
windshield with alcohol s uch as methanol or similar. After drying, wipe 
with 3% ~10% ammonia. Wipe with a dry cotton cloth after drying.  
6.1.1.4.  During the test, the heat source of the defrosting system is provided by 
engine coolant, lubricant or other heat sources.  
6.1.1.5.  The engine speed at neu tral should be no more than 50% of the 
maximum power speed ( Within 5 minutes  from the start of the test, 
programmed  “fast idle speed” can be used [ recommended by manufacturers  
for cold weather engine start] ). 
6.1.1.6.  Low temperature room air velocity horizontal co mponent should be 
lower than 2.2 m/s. Its measuring point is as shown in Figure 3.  
6.1.1.7.  The vehicle battery should be full.  
6.1.1.8.  During the test, both the defrosting temperature control and the wind 
speed should be set to “maximum”. The air flow control should be se t to 
“total defrosting”. Air circulation should be set as per vehicle 
manufacturer’s requirements.    GB 11555 -200× 
6.1.1.9.  The voltage on defrosting system terminals should not be more than 
20% higher than the system’s rated voltage.  
6.1.1.10.  During the test, if windscreen wiper can opera te automatically without 
manual assistance , then it can be used at any time.  
6.1.1.11.  During the test, engine hood, doors and other apertures should be 
closed apart from air circulation inlet and outlet.  If required by vehicle 
manufacturer, 1 or 2 windows can be op ened at the start of the demisting 
test. Total opening clearance should be no more than 25mm.  
6.1.2.  Test instrument, device and requirements  
6.1.2.1.  The jet gun should meet the following requirements:  
a) Diameter of the nozzle: 1.7mm ;  
b) Operating pressure: 350 kPa±20  kPa;  
c) Fluid velocity: 0.395  L/min ;  
d) The diameter of the jet prick: (200mm away from nozzle) 300 mm±50  mm. 
6.1.2.2.  Thermometer or other temperature measurement instruments.   
6.1.2.3.  Engine speedometer.   
6.1.2.4.  Stopwatch or other timing instruments.   
6.1.2.5.  Anemometer or other spee d measurement instruments.   
6.1.2.6.  Voltage gauge.   
6.1.2.7.  Special pencil , charts and cameras.   
6.1.3.  Test procedure  
6.1.3.1.  Turn off the ignition after the test vehicle is brought into the cold room. 
At least 10 hours is required for the vehicle to be kept under the test 
temperature.  If the temperatures of the engine coolant, lubricant, etc are 
known to stay constant at the test temperature, this time can be reduced.  
6.1.3.2.  After procedures in 6.1.3.1 have been carried out , use the jet gun 
specified in 6.1.2.1, spray water (volume = 0.044 g/ cm2 x windshield area) 
even ly onto the exterior  surface of the windshield to generate an even layer 
of ice.  The nozzle should be perpendicular to the windshield surface with a 
distance of 200mm ~250mm.  
6.1.3.3.  After the ice is formed, the vehicle should be kept in the cold room for 
30 to 40 minutes . Then 1 or 2 testers should enter the vehicle and start the 
engine ( external devices can be used to start the engine if necessary). When 
the engine starts running, turn on the defrosting system.  Test is considered 
to have started.  
6.1.3.4.  Once the test is started, testers should mark the contour of the 
defrosted area on the interior surface of the windshield every 5 minutes . 
Signs  indicating driver’s side should also be marked.  
6.2. Windshield demisting test method  
6.2.1.  Test conditions  
6.2.1.1.  Test is conducted under the temperature of -3°C±1°C 
6.2.1.2.  Before the test, clean any smears on both the inside and outside of the 
windshield with alcohol such as methanol or similar. After drying, wipe 
with 3% ~10% ammonia. Wipe with a dry cotton cloth after drying.    GB 11555 -200× 
6.2.1.3.  Test room temperature an air velocity should be measured. The 
measuring position is as shown in Figure 3.  
6.2.1.4.  Cold  room air velocity horizontal component should be lower than 
2.2m/s.  
6.2.1.5.  The engine speed at neutral should be close to but no more than 50% 
of the maximum power speed.  
6.2.1.6.  During the test, engine hood, doors and other apertures should be 
closed apart from air circulation inlet and outlet. If required by vehicle 
manufacturer, 1 or 2 windows can be opened at the start of the demisting 
test. Total opening c learance should be no more than 25mm (vertical).  
6.2.1.7.  The voltage on defrosting system terminals should not be more than 
20% higher than the system’s rated voltage.  
6.2.1.8.  The vehicle battery should be full.  
6.2.2.  Test instrument, device and requirements  
6.2.2.1.  The steam generator  used in the test (see Figure 4) should meet the 
following requirements:  
 
 
 
Figure 4 Steam generator legend  
 
a) Container with a minimum water volume of 2.25L ;  
b) Under -3°C±1°C, the heat loss at boiling point should be no more than 75W ; 
c) The b lower should have a capacity of 4.2m3/h~6.0m3/h under 50Pa static pressure ; 
d) There are 6 vent holes (diameter = 6.3mm ) on top of the steam generator;  
e) The capacity of the steam generator under -3°C±1°C is n×(70 g/h±5g/h ). 
 Note: “n” is the number of se ats as per manufacture’s specification.  
f) See Table 1 for the dimension and material of the steam generator.  Air Blower  
Diffusion chamber  
Nozzle  
Heat insulation water tank  
Heating element  Air and  steam  
Steam  
Water    GB 11555 -200× 
 
Table 1 The dimension and material of the steam generator  
 
Parts  Dimension  Material  
Nozzle  Length: 100mm  
Inside diameter: 15mm  Brass  
Diffusion  chamber  Length: 115mm  
Diameter: 75mm  
6 steam vents (diameter = 
6.3mm) evenly set at the 
bottom of the diffusion 
chamber (gap = 25mm)  Brass tube (wall thickness = 
0.4mm)  
 
6.2.2.2.  DC adjustable regulated voltage power.  
6.2.2.3.  Engine speedometer or other measuring instrum ents.  
6.2.2.4.  Anemometer or other measuring instruments.  
6.2.2.5.  Thermometer or other measuring instruments.  
6.2.3.  Test procedures  
6.2.3.1.  Determine the A and B areas of the windshield as per specification in 
chapter 4.  
6.2.3.2.  The steam generator should be placed behind the backrests of front  
seats. The air vent should be at 580mm±80mm above the R point of the 
driver’s seat . If the seat backrest is adjustable, it should be adjusted to the 
specified angle . If there is not enough room behind the seat backrest, then 
the steam generator can be pla ced in front of the backrest, nearest to the 
location specified above.  
6.2.3.3.  Drive the vehicle into the test room and then turn off the ignition.  
Lower the room temperature until the engine coolant, lubricant and vehicle 
internal temperature stay constant at -3°C±1°C. 
6.2.3.4.  Heat the steam generator (with at least 1.7L water) to boiling point. 
After it  has stabilized, place it in the vehicle and shut the doors.  
6.2.3.5.  After 5 minutes, 1 or 2 testers enter the vehicle. The steam volume 
discharged from the generator should be deducted  by 70g/h±5g/h for each 
tester entering the vehicle.  
6.2.3.6.  1 minute after the testers have entered the vehicle, start the engine as 
per manufacturer’s specification. Operate the demisting system as per 
6.2.1.5 and set the temperature control as per manufac turer’s requirement.  
The test is then considered started.  
6.2.3.7.  10 minutes after the test is started, record test conditions and draw or 
take photos of the contour of the demisted area. The driver’s position 
should also be recorded . 
   GB 11555 -200× 
 
Appendix A  (Reference Appe ndix)  The correlation of the chapter 
numbering in this standard and 78/317/EEC  
Table A.1 lists the correlation of the chapter numbering in this standard and 78/317/EEC.  
 
Table A.1 The correlation of the chapter numbering in this standard and 78/317/EEC  
 
Chapter numbering in this standard  Correlated chapter numbering of  78/317/EEC  
1  1  
2  —  
3  2  
—  2.1-2.14  
3.1  2.15  
3.2  2.16  
3.3  2.17  
3.4  2.18  
3.5  2.19  
3.6  2.20  
3.7  —  
3.8  2.8  
3.9  2.9  
—  3  
—  3.1-3.3  
—  4  
—  Appendix 1  
4.1-4.7  
4  Appendix 4  1, 2  
5  5  
5.1  5.1  
5.2  5.2  
6  6  
6.1  6.1  
6.2  6.2  
6.2.1 , 6.2.3  Appendix 1  
6.2.1 - 6.2.7  
6.2.2  Appendix 5  a) -e) and Table 1  
—  Appendix 2  
—  Appendix 3  
Appendix A  —