DRAFT UGANDA STANDARD  
  DUS 775-1 
Second  Edition  
 2023-06-dd 
 
 
 Reference number  
WDUS 775-1: 2022 
© UNBS 2022   
  
Retro -reflective registration plates for motor vehicles — 
Specification — Part 1: Blanks  (metal)  
 US 775-1: 2022  
ii © UNBS yyyy – All rights reserved  
 Compliance with this standard does not, of itself confer immunity from legal obligations  
A Uganda Standard does not purport to include all necessary provisi ons of a contract. Users are 
responsible for its correct application  
© UNBS yyyy  
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilised in any 
form or by any means, electronic or mechanical, including ph otocopying and microfilm, without prior written 
permission from UNBS.  
Requests for permission to reproduce this document should be addressed to  
The Executive Director  
Uganda National Bureau of Standards  
P.O. Box 6329  
Kampala  
Uganda  
Tel: +256 41 4 333 2 50/1/2/3 
Fax: +256 41 4 286 123  
E-mail: info@unbs.go.ug  
Web: www.unbs.go.ug  US 2022 -n:yyyy  
© UNBS yyyy – All rights reserved  iii 
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ .............................  v 
1 Scope  ................................ ................................ ................................ ................................ ......................  1 
2 Normative references  ................................ ................................ ................................ ............................  1 
Terms and definitions  ................................ ................................ ................................ ................................ ........  1 
4 Requirements  ................................ ................................ ................................ ................................ .........  2 
4.1 Type of blank  ................................ ................................ ................................ ................................ .........  2 
4.2 Materials  ................................ ................................ ................................ ................................ ........................  2 
4.2.1 Metal  ................................ ................................ ................................ ................................ ...........................  2 
4.2.2 Retro -reflective material  ................................ ................................ ................................ ...........................  2 
4.3 Embossed border colour and luminance factor  ................................ ................................ .......................  4 
4.3.1 Colour of embossed border  ................................ ................................ ................................ .....................  4 
4.3.2 Luminance factor  ................................ ................................ ................................ ................................ ....... 4 
4.4 Shape and dimensions  ................................ ................................ ................................ ................................  4 
4.5 Preparation of the plate  ................................ ................................ ................................ ...............................  4 
4.5.1 Cleanliness  ................................ ................................ ................................ ................................ .................  4 
4.5.2 Coating of aluminium  ................................ ................................ ................................ ................................  4 
4.6 Application of retro -reflective material  ................................ ................................ ................................ ...... 4 
4.7 Embossed border  ................................ ................................ ................................ ................................ .........  5 
4.8 Colour strip  ................................ ................................ ................................ .......Error! Bookmark not defined.  
4.9 Workmanship  ................................ ................................ ................................ ................................ ................  5 
5.0 Performance tests  ................................ ................................ ................................ ................................ ........  5 
5.1 Resistance to weathering  ................................ ................................ ................................ ............................  5 
5.2 Resistance to impact ................................ ................................ ................................ ................................ .... 5 
5.3 Resistance to scratchin g ................................ ................................ ................................ .............................  6 
5.4 Resistance to salt fog  ................................ ................................ ................................ ................................ .. 6 
5.5 Resistance to bending  ................................ ................................ ................................ ................................ . 6 
6 Inspection and methods of test  ................................ ................................ ................................ .....................  6 
6.1 General  ................................ ................................ ................................ ................................ ..........................  6 
6.2 Inspection  ................................ ................................ ................................ ................................ ......................  6 
6.3 Test specimens  ................................ ................................ ................................ ................................ .............  6 
6.4 Resistance to weathering  ................................ ................................ ................................ ............................  7 
6.4.1 Apparatus  ................................ ................................ ................................ ................................ ...................  7 
6.4.2 Temperature measurement  ................................ ................................ ................................ ......................  7 
6.4.3 Temperature control ................................ ................................ ................................ ................................ .. 7 
6.4.4 Procedure  ................................ ................................ ................................ ................................ ...................  8 
6.5 Resistance to impact ................................ ................................ ................................ ................................ .... 8 
6.5.1 Apparatus  ................................ ................................ ................................ ................................ ...................  8 
6.5.2 Procedure  ................................ ................................ ................................ ................................ ...................  8 
6.6 Resistance to scratching  ................................ ................................ ................................ .............................  9 
6.6.1 Apparatus  ................................ ................................ ................................ ................................ ...................  9 
6.6.2 Procedure  ................................ ................................ ................................ ................................ ...................  9 
6.7 Resistance to salt fog  ................................ ................................ ................................ ................................ .. 9 
6.7.1 Apparatus  ................................ ................................ ................................ ................................ ...................  9 
6.7.2 Salt solution  ................................ ................................ ................................ ................................ .............  10 
6.7.3 Conditions of test  ................................ ................................ ................................ ................................ .... 10 
6.7.4 Procedure  ................................ ................................ ................................ ................................ .................  10 
6.8 Bending test  ................................ ................................ ................................ ................................ ................  11 
6.9 Colour and luminance factor test  ................................ ................................ ................................ .............  11 
6.10 Photometric test  ................................ ................................ ................................ ................................ ....... 11 US 775-1: 2022  
iv © UNBS yyyy – All rights reserved  
 7 Packing and marking  ................................ ................................ ................................ ................................ .... 11 
7.1 Packing  ................................ ................................ ................................ ................................ .......................  11 
7.2 Marking  ................................ ................................ ................................ ................................ .......................  11 
Annex  A (normative)  Quality verification of  metal blanks for retro -reflective registration plates  .........  12 
Bibliography  ................................ ................................ ................................ ................................ .....................  13 
 US 2022 -n:yyyy  
© UNBS yyyy – All rights reserved  v 
 Foreword  
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministr y of Trade , Industry and 
Cooperatives established under Cap 327 , of the Laws of Uganda , as amended .  UNBS is mandated to co -
ordinate the elaboration of standards and is  
(a) a member of International Organisation for Standardisation (ISO) and  
(b) a contact point for the WHO/FAO Codex Alimentarius Commission on Food Standards, and  
(c) the National Enquiry Point on TBT  Agreement  of the World Trade Organisation (WTO).  
The work of preparing Uganda Standards is carried out through Technical Committees. A Technical 
Committ ee is established to deliberate on standards in a given field or area and consists of key stakeholders 
including government, academia, consumer groups, private sector and other interested parties.  
Draft Uganda Standards adopted by the Technical Committee are widely circulated to stakeholders and the 
general public for comments. The committee reviews the comments before recommending the draft standards 
for approval and declaration as Uganda Standards by the National Standards Council.  
The committee responsi ble for this document is Technical Committee UNBS /TC 117, Transport vessels and 
accessories . 
This second  edition cancels and replaces the first edition ( US 775-1:2022 ), which has been technically 
revised.  
US 775  consists of the following parts, under the general title Retro -reflective registration plates for motor 
vehicles — Specification   
  Part 1: Blanks (metal)  
  Part 2: Metallic registration plates  
 UGANDA STANDARD  US 775-1: yyyy  
 
© UNBS yyyy – All rights reserved  1 
 Retro -reflective plates for motor vehicles — Specification  — 
Part 1: Blanks (metal)  
1 Scope   
1.1  This p art of US 775 specifies requirements for the type of blank intended for use in the production of the 
embossed registration plates that are covered by US 775 -2.  
1.2 Except under the certification mark scheme, a special agreement between the manufacturer an d the 
purchaser is required for assessment of compliance with the requirements of US 775 -1 of those blanks on 
which the retro -reflective material is applied during the process of embossing the registration number 
paragraph.  
2 Normative references   
The foll owing referenced documents referred to in the text in such a way that some or all of their content 
constitutes requirements of this document. For dated references, only the edition cited applies. For undated 
references, the latest edition of the referenced  document (including any amendments) applies.  
ASTM G 154 , Standard practice for operating fluorescent light apparatus for UV exposure of non-metallic  
materials  
CDUS ISO 7591  Road vehicles — Retro -reflective registration plates for motor vehicles and traile rs — 
Specification  
US 775 -2:2008, Retro -reflective registration plates for motor vehicles — Specification — Part 2: Metallic 
registration number plates   
 Terms and definitions   
For the purposes of this document, the following terms and definitions apply.  
ISO and IEC maintain terminological databases for use in standardization at the following addresses:  
— ISO Online browsing platform: available at http://www.iso.org/obp  
3.1  
blank  
flat metal plate that has, on one side, an embossed border and at least th e area within this border covered 
with retro -reflective material, the material being supplied as a loose sheet if it is intended to be subsequently 
applied as part of the embossing process of the registration number  
3.2  
category L motor vehicle  
motor veh icle that has fewer than four wheels text of the definition  
3.3  
embossing  
process by which a raised border is embossed onto a plate (to form a blank) or by which characters are so 
embossed onto a blank that they stand out in relief on the retro -reflectiv e surface of a registration plate   
2 © UNBS yyyy – All rights reserved  
 3.4 
illuminants A and D65  
illuminants A and D65 as defined by the International Commission on illumination (CIE) in Publication 15  
(E.1.3.1)  
3.5   
luminance factor  
(at a point on the surface of a non -self-radiating body , in a given direction, and under specific conditions of 
illumination) ratio of the luminance of the material to that of a perfect reflecting diffuser identically illuminated  
3.6 
registration mark/registration number  
combination of letters and numerals a s prescribed by the Traffic and Road Safety Act, 1998 as amended   
3.7  
registration plate;  
plate that displays the registration mark of a motor vehicle or trailer  
3.8  
retro -reflection  
reflection in which light is reflected in directions close to the dir ection of incidence, irrespective of the angle of  
incidence at the reflecting surface  
4 Requirements  
4.1 Type of blank  
A blank shall be of a type in which the front face is completely covered with retro -reflective material and is 
intended for use in an em bossing process in which the raised surfaces of the characters and the embossed 
border are coated.  
4.2 Materials  
4.2.1 Metal  
The metal base of a blank shall be of aluminium sheet material of thickness at least 1.0 mm ± 0.1 mm and 
shall be suitable for th e embossing process.  
4.2.2 Retro -reflective material  
4.2.2.1  Colour and luminance factor  
4.2.2.1.1 When determined in accordance with 6.8, the colour of the retro -reflective material shall be yellow, 
blue, red or white  and the chromaticity co -ordinates  shall be within the area on a chromaticity diagram defined 
by the points of the appropriate values given in Table 1.  
4.2.2.1.2  When determined in accordance with 6.8, the luminance factor of the material shall be at least 
the appropriate value given in Table 1  
 
Table  1 — Chromaticity co -ordinates and luminance factors  
Coloura Coordinate  Value of coordinate  Luminance US 2022 -n: yyyy  
© UNBS yyyy – All righ ts reserved  3 
 1 2 3 4 factor, β 
White  x 0,355  0,305  0,285  0,335  
≥ 0,35  
y 0,355  0,305  0,325  0,375  
Blue  X 0,181 0,270 0,230 0,10 3 ≥ 0,05  
y 0,069 0,220 0,250 0,246 
Red x 0,690  0,570 0,545 0,655  ≥ 0,05  
y 0,310  0,315  0,34 0 0,345  
Yellow  x 0,545 0,487 0,427 0,465 ≥ 0,17  
y 0,45 4 0,423 0,483 0,534 
Dark green  x 0,200  0,300 0,300 0,200  0,02 ≤ β ≤ 
0,10  
y 0,450 0,450 0,550 0,550 
Military green  x 0,300 0,400 0,400 0,300  0,05 ≤ β ≤ 
0,15  y 0,400 0,400 0,500 0,500 
Electric green  x 0,220 0,320 0,320 0,220 0,10 ≤ β ≤ 
0,20  
y 0,510 0,510 0,610 0,610 
 
4.2.2.2 Coefficients of retro -reflection   
When the coefficients of retro -reflection of the m aterial are determined in accordance with 6.9, they shall be at 
least the relevant values given in Table 2.  
Table  2 — Coefficients of retro -reflection  
Observation angle, 
degrees  Entrance angle, 
degrees  Coefficient of retro – reflection when measured 
with standard illuminant A, cd(/lx.m2) min.  
 
Graphicb Yellow  White  
0.33a) 
1.5 5a) 
30 35 
1.5 35 
1.5 50 
2.0 
The coefficient of retro -reflection at an angle of observation and an entrance angle of 0.33° and 5° respectively, shall not 
exceed 100 cd/(lx.m2) for yellow material and 160 cd/(lx.m2) for white material.  
4.2.2.3 Flexibility  
After wrapping a piece of retro -reflective material of size 200 mm x 100 mm, complete with protective lining 
for surface outwards, lengthwise around a mandrel of diameter 20 m m and length at least 250 mm (that is, 
the retro -reflective material has been wrapped with its longer axis parallel to that of the mandrel), there shall 
be no evidence of cracking of the retro -reflective material.   
4 © UNBS yyyy – All rights reserved  
 4.2.2.4 Validation mark  
The blank mater ial shall bear a serial number and a validation mark that identifies the manufacturer of the 
material.  
4.3 Embossed border colour and luminance factor  
4.3.1 Colour of embossed border  
The colour of the embossed border shall match the colour of the licenc e number  
4.3.2 Luminance factor  
When the luminance factor of the colours blue, red, green and white  is determined in accordance with 6.8, it 
shall be  not less than 0.12.   
4.4 Shape and dimensions  
Blanks  shall be rectangular, with corners rounded to a rad ius of 12 mm, be free from sharp edges and burrs, 
and shall be of one of the sizes specified under annex A  of US 775 -2. 
4.5 Preparation of the plate  
4.5.1 Cleanliness  
The surface of the metal base to which the retro -reflective material is applied shall b e dry and free from 
grease, oil, corrosion and any form of contamination before the retro -reflective material is applied and, when 
relevant, before it is coated.  
4.5.2 Coating of aluminium  
 4.5.2.1  Aluminium blanks  
The surfaces of each blank that have an aluminium base and that are coated [before the application of the 
retro-reflective material shall be coated with  
a) a powder coating of dry film thickness at least 35 μm, or  
b) a suitable surface -conversion coating, followed by a coat (of a dry film thickne ss at least 20 μm) of a 
baking enamel.  
4.6 Application of retro -reflective material  
Blanks, other than those on which the retro -reflective material is intended to be applied during the process of 
embossing the registration number, shall have the material  applied to the front surface. The retro -reflective 
material shall be of such a size that, the retro -reflective material covers the entire surface of the blank so that 
at no part is the width of the retro -reflective material less than the width of the blan k by more than 2 mm,  and 
at no part is the distance between the edges of the retro -reflective material and the adjacent edges of the 
blank more than 1.3 mm.  US 2022 -n: yyyy  
© UNBS yyyy – All righ ts reserved  5 
 4.7 Embossed border  
The embossed border of a blank shall be of curved or flat cross -section, gen erally as given in Figure 1. The 
embossing shall extend around the periphery of the blank and shall have an overall width of 5 mm ± 1 mm 
and a height above the surface of the blank of, not less than 1 mm and not more than 2 mm.  
 
Figure 1 — Typical embo ssed border   
4.8 Workmanship  
Blanks shall be free from creases, crevices and sharp or jagged edges, and retro -reflective and coated 
surfaces shall be free from creases, cracks, chips, blisters, discoloration and spots.  
5.0 Performance tests  
5.1 Resista nce to weathering  
When blanks are tested in accordance with 6.4,  
a) the chromaticity co -ordinates shall remain within the area on the appropriate chromaticity diagram as  
defined in 4.2.2.1 ;  
b) the coefficient of retro -reflection at an angle of observation an d an entrance angle of 0.33 ° and 5 ° 
respectively, shall be at least 80 % of the minimum values given in Table 2;  
c) the retro -reflective material shall show no sign of cracking, blistering, or loss of adhesion; and  
d) when relevant, the painted or powder -coate d surface shall show no sign of chalking or checking.  
5.2 Resistance to impact  
When blanks are tested in accordance with 6.5, the retro -reflective material and (when relevant),  the painted 
or powder -coated surface shall show no sign of cracking or loss o f adhesion.  5±1  
6 © UNBS yyyy – All rights reserved  
 5.3 Resistance to scratching  
When blanks are tested in accordance with 6.6, the scratch produced  
a) on the retro -reflective surface shall not have penetrated the material surface, and  
b) on the painted or powder -coated surface (when relevant), sh all be free from jagged edges and shall  
not  have penetrated through to the substrate.  
5.4 Resistance to salt fog  
When blanks are tested in accordance with 6.6, no surface shall  show any sign of delamination, edge lifting or 
loss of adhesion. In the cas e of a retro -reflective surface, there shall be no sign of corrosion or blistering. In 
the case of a painted or powder -coated surface, any blister or creep (or both) or corrosion shall not extend 
further than 2 mm on each side of the scribe mark.  
5.5 Resis tance to bending  
When blanks are tested in accordance with 6.8, there shall, after each bending operation, be no sign of 
cracking of the metal, or of cracking or loss of adhesion of the retro -reflective material or (when relevant) of 
the paint or powder c oating.  
6 Inspection and methods of test  
6.1 General  
In the case of blanks where the retro -reflective material is intended to be applied as part of the embossing 
process of the registration number, inspection and tests shall be carried out on test speci mens on which the 
retro-reflective material has been permanently applied using the registration number embossing process but 
without a number having been embossed.  
6.2 Inspection  
Visually examine and measure each blank in the sample for compliance with a ll the appropriate requirements 
of this standard for which tests to assess compliance are not given in 6.4 to 6.8 (inclusive).  
6.3 Test specimens  
From sample blanks, cut the following test specimens:  
a) resistance to weathering : one test specimen of width at least 70 mm and of length at least 150 
mm, and that has not more than one cut edge;  
b) resistance to impact : one test specimen of any convenient size; the test may be carried out on an 
end of the specimen cut in terms of (e) below before it is subjected t o bending;  
c) resistance to scratching : one test specimen of width at least 55 mm and of length at least 100 mm;  
d) resistance to salt fog : one test specimen in the case of a blank without any paint or powder coating 
on  the rear surface, and two test specimen s in other cases, each of width at least 100 mm and of 
length at  least 100 mm and that have not more than two cut edges;  
e) bending test : one test specimen of width between 100 mm and 120 mm and of length at least 250 
mm, and that has embossed on it one cha racter of a registration mark that complies with the  
appropriate requirements of US 775 -2.   US 2022 -n: yyyy  
© UNBS yyyy – All righ ts reserved  7 
 6.4 Resistance to weathering  
6.4.1 Apparatus  
A weathering unit that  has the following features:  
a) Test chamber  constructed of corrosion -resistant materials enclo sing eight fluorescent UV lamps, a 
heated water pan, test specimen racks that constitute the side walls of the chamber, and provisions 
for controlling and recording operating times and temperatures  
b) Lamps,  of type UVB 313 fluorescent UV lamps or equivalent , the spectral energy distribution curve 
having a maximum at a wavelength of 313 nm with less than 1 % of the peak intensity at 280 nm. 
The lamps are of length 1 220 mm and of nominal rating 40 W when operated from a ballast that 
provides a controlled curr ent of 430 mA at 102 V.  
c) Lamp and test specimen arrangement  with the lamps mounted in two banks of four lamps each to 
provide a uniform distribution of irradiance. The lamps in each bank are mounted parallel to each 
other at 70 mm centres. The test specime ns are mounted in two stationary racks each of height 300 
mm and of  width 1 154 mm, the test surface being in each case parallel to the plane of one bank of 
lamps and at a distance of 50 mm from the nearest surface of the lamps.  
d) Condensation mechanism  where water vapour is generated by the heating of a water pan that 
extends under the entire specimen area and contains water of depth 25 mm. The back surface of 
each specimen is exposed to the cooling effect of the ambient room air. The resulting heat transf er 
causes water vapour, saturated with air, to condense on the test surface. The specimens are so 
arranged that condensate runs off the test surface by gravity and is replaced by fresh condensate in 
a continuous process. Vents along the bottom of the test chamber are provided to admit ambient air 
and so prevent oxygen depletion of the condensate.  
e) Water supply  with an automatic control to regulate the level in the water pan. Distilled, de -ionized, 
or potable tap water may be used.  
f) Cycle timer  that is conti nuously operating provided to program the selected cycle of UV radiation 
periods and condensation periods. An hour meter is provided to record the total time of operation 
and total time of UV exposure.  
6.4.2 Temperature measurement  
6.4.2.1  The temperatur e is measured by means of a thermometer, the bulb of which is inserted in a black 
aluminium panel of size 75 mm x 100 mm x 2.5 mm. The thermometer is accurate to 1 °C through a range of 
30 °C to 80 °C. The indicator of the thermometer is located outside th e test chamber.  
6.4.2.2  The black aluminium panel and thermometer bulb are so positioned in the centre of the exposure rack 
that they are subjected to the same conditions as the specimens.  
6.4.3 Temperature control  
6.4.3.1  During UV exposure, the selec ted equilibrium temperature is maintained within 3 °C by the supply of 
heated air to the test chamber.   
6.4.3.2 During condensation exposure, the selected equilibrium temperature is maintained within 3 °C by the 
heating of the water in the pan.  
6.4.3.3  The UV and condensation temperature controls are independent of each other.   
8 © UNBS yyyy – All rights reserved  
 6.4.3.4 Doors are located on the room airside  of the specimen rack, to act as insulation during the UV 
exposure and to minimize draughts. The doors do not interfere with the room air-cooling  of the specimen 
during the condensation exposure.  
6.4.4 Procedure  
6.4.4.1   Seal the cut edge of each specimen.  
6.4.4.2   Mount the test specimens in the specimen racks, with the test surfaces facing the lamps.  
6.4.4.3   Select the following c ycle conditions:  
a) 4 h UV exposure at 60 °C; and then  
b) 4 h condensation exposure at 50 °C.  
6.4.4.4 Except for servicing the apparatus and inspecting the specimens, repeat the cycle continuously for 
240 h.  
6.4.4.5  At regular intervals during the specified  exposure period, examine the specimens under 10x 
magnification.  
6.4.4.6  Check for compliance with 5.1.  
6.5 Resistance to impact  
6.5.1 Apparatus  
6.5.1.1 Striker,  a cylindrical piece of steel of length and diameter approximately 230 mm and 25 mm 
respec tively, that has a hardened steel ball of diameter 12.7 mm ± 0.1 mm mounted at its bottom end and a 
total mass of 900 g ± 10 g  
6.5.1.2 Drop tube,  a slotted or split vertical tube graduated in millimetres, of approximate length 500 mm and 
of diameter large  enough to enable the striker to drop freely through it  
6.5.1.3 Base plate,  a horizontal steel plate that has a hole of diameter 16 mm, the plate being so placed that 
the hole is concentric with the opening of the tube  
6.5.2 Procedure  
6.5.2.1 So place t he specimen over the hole in the base plate that the striker will fall onto a part of a retro -
reflective surface of the specimen.  
6.5.2.2 Raise the striker to the appropriate height and allow it to fall with an energy of 1.15 J for aluminium 
blanks.  
6.5.2.3 When relevant, repeat 6.5.2.1 and 6.5.2.2, but with the point of impact being on a part of a painted or 
powder -coated surface.  
6.5.2.4  Examine the dented part(s) of the specimen under 10x magnification for compliance with 5.2.  US 2022 -n: yyyy  
© UNBS yyyy – All righ ts reserved  9 
 6.6 Resistance to scra tching  
6.6.1 Apparatus  
6.6.1.1 Needle and arm : a needle with a hardened steel hemispherical point of diameter 1 mm, fixed 
vertically, point downwards, to the end of a counterpoised horizontal arm. The horizontal arm provides for the 
loading of mass  piece s above the needle direct, and it may be set in equilibrium on its fulcrum by adjustment 
of the countermass before mass  pieces are loaded above the needle.  
6.6.1.2  Mass  pieces , a set of forty 50 g mass  pieces  
6.6.1.3 Base with sliding specimen holder , that moves freely and automatically on its base under the 
loaded needle (which is perpendicular to the specimen holder)  
6.6.1.4 Electric current supply and ammeter . The needle and specimen holder are so connected in series 
with an ammeter and an electric c urrent supply that, when the painted or powder -coated surface of a 
specimen is penetrated, the needle makes electrical contact with the underlying metal, and this penetration is 
indicated by a flow of current through the ammeter.  
6.6.2 Procedure  
6.6.2.1 In the case of a retro -reflective surface, set the horizontal arm in equilibrium, with the electric current 
supply and ammeter not in use. Clamp the specimen to the specimen holder, with the material to be tested 
facing upwards. Load the needle with mass  pieces of total mass 2000 g and lower the needle carefully onto 
the material surface while starting to slide the holder. Alternatively, so put the end of the needle on a razor 
blade on the material surface that the needle can slide off the sharp edge of the  blade onto the surface. Slide 
the holder at a uniform speed of approximately 30 mm/s for a distance of about 90 mm.  
6.6.2.2  Examine the edges of the groove under 10x magnification.  
6.6.2.3  Check for compliance with the relevant requirements of 5.3.  
6.6.2.4  Repeat 6.6.2.1 to 6.6.2.3 on two other parts of the material surface.  
6.6.2.5  In the case of a painted or powder -coated surface, carry out the test as given in 6.6.2.1 to 6.6.2.4, 
but with the electric current supply and ammeter in use.  
6.7 Resi stance to salt fog  
6.7.1 Apparatus  
A fog cabinet that  has the following features:  
(a) Exposure chamber , made from, or coated with, a corrosion -resistant material and, so constructed 
that the salt fog circulates freely and equally about all specimens, and th at has baffles to prevent the 
salt fog from striking the specimens direct  
(b) Racks for supporting the specimens , removable and made from, or coated with, a corrosion -
resistant material and so constructed that the specimens are held without touching one anoth er or any 
other metal and that salt solution will not drip from one specimen onto another.  
(c) Salt solution reservoir , of adequate size to produce the required quantity of salt fog and made from, 
or coated with, corrosion -resistant material. It is so constru cted that there is no recirculation of the salt 
solution  
(d) Atomizing nozzles , plastics nozzles so designed that they will produce a finely divided salt solution 
fog   
10 © UNBS yyyy – All rights reserved  
 (e) Air supply : a compressed air supply for the atomizing nozzles, filtered to remove all impur ities. 
Means are provided to humidify and heat the compressed air as necessary. The air pressure is 
constant to within 700 Pa and sufficient to produce a finely divided salt solution fog.  
(f) Heating of chamber and temperature control : the exposure chamber is  heated and its temperature 
is controlled by means of a thermostat.  
  NOTE – An immersion heater should not be used.  
6.7.2 Salt solution  
The salt solution is made up as follows:  
a) Salt: sodium chloride containing sodium iodide not exceeding 1 g/kg of sal t and total impurities not  
exceeding 3 g/kg of salt, calculated on the dry basis  
b) Water  that contains total solids not exceeding 200 mg/kg of water  
c) The salt solution is prepared by dissolving 5 parts ± 0.5 parts (by mass) of salt in 95 parts (by mass) 
of water and filtering the solution.  
6.7.3 Conditions of test  
6.7.3.1  Temperature  
Maintain the temperature in the exposure zone at 33 °C to 36 °C.  
6.7.3.2  Salt fog  
Ensure that the degree of atomization of the salt solution is such that suitable fog co llectors placed at any 
point in the exposure zone will collect, over an average running period of at least 16 h, 65 mL to 375 mL of 
solution per hour per square metre of horizontal collecting area. Ensure that the solution so collected has a pH 
value of 6. 5 to 7.2 when measured electrometrically.  
6.7.4 Procedure  
6.7.4.1 In the case of specimens that have a paint or powder coating, use a suitable cutting tool and carefully 
make (with the cutting edge of the cutting tool held at an angle of about 30° to the  surface and the plane of the 
blade perpendicular to that surface) a scribe mark of length about 75 mm, by cutting through the coating to the 
base.  
6.7.4.2 Establish the test conditions in the exposure chamber. Mount the specimens on the supporting racks 
and insert the racks in the exposure chamber.  
6.7.4.3 Close the exposure chamber and operate the cabinet continuously for 24 h.   
5.7.4.4 After the test period, remove the specimens and rinse them thoroughly with distilled water. Examine 
the following for  compliance with the applicable requirements of 5.4:  
a) when relevant, the paint or powder coating, immediately after removal of the specimens from the  
exposure chamber; and  
b) the retro -reflective material, after a 24 h recovery period has elapsed.  US 2022 -n: yyyy  
© UNBS yyyy – All righ ts reserved  11 
 6.8 Bend ing test  
So place the unlaminated surface of the test specimen  against a mandrel of diameter 50 mm ± 1 mm that the 
line of maximum bending coincides with the vertical centre -line of the letter or numeral. Taking about 3 s, bend 
the specimen through an ang le of 90° ± 2° over the mandrel, and then examine it for compliance with 5.5. 
Immediately following this procedure, and taking about 3 s, so bend the specimen back through the same 
angle that it is in approximately its original alignment and again examine it for compliance with 5.5.   
6.9 Colour and luminance factor test  
Determine the chromaticity co -ordinates and luminance factors of the relevant areas of the specimen by 
means of a spectrophotometer or other equally suitable colour measuring device, using  Standard Illuminant 
D65 and 45/0 geometry.  
Check for compliance with 4.2.2.1 .  
6.10 Photometric test  
Determine the coefficients of retro -reflection, using the values of observation angle and entrance angle given 
in Table 2. On each specimen, take the av erage of two readings at rotation angles (about the reference axis) 
that are 90° apart. Check for compliance with 4.2.2.2.   
7 Packing and marking  
7.1 Packing  
The blanks and, when relevant, the retro -reflective material shall be so packed as to ensure tha t they are not 
damaged during normal handling, transportation and storage.  
7.2 Marking  
Each blank shall bear the manufacturer’s trade name or trade mark, serial number, Uganda flag and security  
hologram in legible and indelible marking, on the surface co vered or not covered by the retro -reflective 
material. The Uganda flag, security hologram and serial number shall be on the left hand side of plate covered 
by the retro -reflective material. The Uganda flag shall be on top, security hologram in the middle a nd serial 
number at the bottom in that order.   
12 © UNBS yyyy – All rights reserved  
 Annex  A 
(normative)  
 
Quality verification of metal blanks for retro -reflective registration plates  
When a purchaser requires ongoing verification of the quality of metal blanks for retro -reflective registration  
plates, it is suggested that, instead of concentrating solely on evaluation of the final product, he also directs 
his attention to the manufacturer's quality system. In this connection it should be noted that US ISO 9001 
covers the provision of an integra ted quality system . US 2022 -n: yyyy  
© UNBS yyyy – All righ ts reserved  13 
 Bibliography  
[1] US 775 -1:2008 , Retro -reflective registration plates for motor vehicles — Specification — Part 1: Blanks 
(metal)  
[2] ISO 7591 :1982 , Road vehicles — Retro -reflective registration plates for motor vehicles and trailers — 
Specification  
 US 2022 -n: yyyy  
© UNBS yyyy – All rights reserved  15 
 Certification marking  
Products that conform to Uganda standards may be marked with Uganda National Bureau of Standards 
(UNBS) Certification Mark shown in the figure below.  
The use of the UNBS Certification Mark is governed by the Standards Act, and the Regulations made 
thereunder. This mark can be used only by those licensed under the certification mark scheme operated by 
the Uganda National Bureau of Standards and in conjunction with the relevant Uganda Standard. The 
presence of this mark o n a product or in relation to a product is an assurance that the goods comply with the 
requirements of that standard under a system of supervision, control and testing in accordance with the 
certification mark scheme of the Uganda National Bureau of Standa rds. UNBS marked products are 
continually checked by UNBS for conformity to that standard.  
Further particulars of the terms and conditions of licensing may be obtained from the Director, Uganda 
National Bureau of Standards.  
 
 US 2022 -n: yyyy    
 
ICS nn.nnn.nn  
Price based on nn pages  
© UNBS yyyy– All rights reserved