CDC 10 (963) DTZS 
  ICS 01.100.40 
 
© TBS 2022                                                                                                 1st Edition 
  
DRAFT TANZANIA STANDARD 
 
 
Black Lead Pencil - Specification 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
TANZANIA BUREAU OF STANDARDS 
 
 
 
 
CDC 10 (963) DTZS 
© TBS 2022                                                                                                 1st Edition 
 0   Foreword  
 
This Draft Tanzania Standard is being developed by Stationery and Paper Products Technical 
Committee under supervision of the Chemical Division Standards Committee and it is in 
accordance with the procedures of the Bureau. 
 
This Tanzania Standard has been prepared with assistance drawn from: 
 
IS 1375:1981 Specification for Black Lead Pencils , published by Indian Bureau of 
Standards.   
 
For the purpose of deciding whether a particular requirement of this Tanzania Standard is 
complied with, the final value observed or calculated, expressing the result of a test or analysis, 
shall be rounded off in accordance with TZS 4 . 
 
 
                                                     CDC 10 (963) DTZS   
 
© TBS – All rights reserved  
 
DRAFT TANZANIA STANDARD                  CDC 10 (963) DTZS 
 
Black Lead Pencil - Specification 
 
1   Scope 
 
This draft Tanzania Standard specifies the requirements, sampling and test methods for Black 
Lead Pencil. 
  
2   Normative references 
 
The following referenced documents are indispensable for the application of this document. The 
latest edition of the referenced document (including any amendments) applies;  
 
TZS 4 Rounding off numerical values 
 
3   Terms and definitions  
For the purpose of this draft Tanzania Standard the following definitions shall apply: 
 
3.1 black lead pencil   
pencil in which the slip, made basically of graphite and clay, is fixed in a wooden casing 
  
3.2 drawing pencil   
black lead pencil, in different grades; intended for drawing purposes 
 
3.3 carpenter's pencil  
black lead pencil used by carpenters for marking on wood 
 
3.4 stenographer's and reporter's pencil  
black lead pencil used by stenographers and reporters for writing in shorthand 
  
3.5 general writing pencil   
black lead pencil used for general purposes 
 
4 Types and grades 
 
4.1 Types 
Pencils shall be of following types :  
a) Drawing pencils, 
b) Carpenter's pencils,  
c) Stenographer's and Reporter's pencils, and  
d) Pencils for general writing:   
 
4.2 Grades 
4.2.1 Drawing pencils shall be supplied in the following grades, as specified by the manufacture; 
 
6B; 5B; 4B; 3B; 2B; B; HB; H; 2H; 3H;4H; 5H; and 6H.  
 
NOTE - B denotes softness and darkness of pencil and H denotes the hardness of pencil. For example, 
pencil of grade 6B is the softest, darkest pencil and pencil of grade 6H is the hardest, lightest  CDC 10 (963) DTZS  
© TBS – All rights reserved 
   
4.2.2 Pencils for carpenters and for stenographers and reporters shall generally be of grade HB 
only.  
4.2.3 Pencils for general writing shall be supplied in the following grades:  
Hard-H,2H;  
Medium - HB; and  
Soft -B, 2B. 
 
5   Requirements  
 
5.1 Material and workmanship 
 
5.1.1 Slip  
The slip shall be in one piece, of uniform grading, free from grittiness and so basically made of 
graphite and clay as to produce smooth, even and uniform writing. It shall be sufficiently strong to 
withstand sharpening by a sharp knife or standard pencil sharpener and shall not break on 
mending or writing.  
 
4.1.2 Casing 
The casing shall be made from pencil slats. It shall be readily cut with an ordinary pocket knife 
with a reasonably sharp blade. When sharpened with a standard pencil sharpener, the wood shall 
take a smooth and even finish. Both halves of the wood casing shall be securely glued together 
throughout their length. The casing shall enclose the slip in a neat. secure manner, in such a way 
that the slip is centered. The warpage in 80 percent of the sample shall not exceed 0.5 mm, and 
in the remaining 20 percent of the sample, the warpage shall not exceed 1.0 mm. 
 
4.1.3 Shapes   
Carpenter's pencils shall be oval in section; Stenographer's and reporter's pencils shall be round, 
and the section of all other categories of -pencils shall be round or hexagonal, as specified by the 
Manufacture.  
 
 
 
4.2 Specific requirements. 
 
The Pencil, when tested according to the methods prescribed in Annexes A, B, C and D shall 
comply with the specific requirements given in Table 1. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 CDC 10 (963) DTZS 
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Table 1 Specific requirements for Pencil  
S/No. Property Requirement  Test 
method 
i. Blackness of Pencil 
Marking,% 
reflectance  
Stenographer's and reporter's 
 68±3  
Annex A 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 General writing 
pencils,  
  hard grade 7l ±2 
medium grade 70±2 
soft grade 66±2 
 
Carpenter's pencils 
 70±3 
Drawing pencils 
 Grade 6H 77±1 
Grade 5H 75±1 
Grade 4H 74±1 
Grade 3H 73±1 
Grade 2H 71±1 
Grade H 69±1 
Grade HB 68±1 
Grade B 66±1 
Grade 2B 65±1 
Grade 3B 63±1 
Grade 4B 62±1 
Grade 5B 60±1 
Grade 68  59±1 
ii.  
Friction of Slip, max  
0.2  
Annex B 
 
iii. Chemical Inertness of Pencil Markings To pass test Annex C 
 
iv. Gluing and Warpage of Wood Casing To pass test Annex D 
  CDC 10 (963) DTZS  
 
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 5.Dimensions requirements 
 
5.1 Dimensions . 
5.1.1 The length of the pencils shall be 177±3 mm. 
 
5.1.2 The diameter of pencils, other than carpenter's pencils, shall be between 7.5 and 
8.0 mm for varnished or lacquered pencils and between 7.0 and 7.6 mm for unvarnished 
and unlacquered pencils. In the case of hexagonal pencils, the diameter shall be taken as 
the distance between any two opposite corners. 
 
5.1.3 The cross-section of the carpenter's pencils shall be oval with the ends of the major 
axes trimmed straight. The dimensions of the cross sections of carpenters’ pencils shall 
be as indicated in either Fig. 1 A or Fig. 1 B. 
 
Figure 1 Cross Section of Carpenters Pencils 
 
 
5.1.4 The diameter of slips used in the manufacture of pencils, shall be as under:  
 
 
No  
Pencils  
Grades Diameter of Slip 
mm 
1  
Drawing pencils, 6H,5H,4H, 3H, 2H, H and HB 1.90 - 2.30 
2B, 3B and 4B 2.10 - 3.20 
5B and 6B 3.50 - 3.60 
2 Stenographer's and 
reporter's pencils, HB 2.10 - 3.00 
3 General writing pencils, 2H, H, HB 1.90 - 2.30 
B,2B 2.l0 - 3.20 
4 a Carpenter's pencils, HB 4.4 - 5.0 
2.0 -2.5 
a slips of carpenter's pencils shall be rectangular 
 
5.1.5 Pencils in one carton shall be of the same dimension. 
 
 
 
 
 
 
 CDC 10 (963) DTZS 
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  6. Packing and marking  
  
6.1 Packing  
  
Pencils shall be packed in a suitable package that withstand normal handling and transportation 
and that will prevent breakage of the product. 
 
6.2 Marking  
Each pencil shall be legibly and indelibly labelled with the following information:  
a) the name and trade-mark of the manufacturer or the supplier.  
b) grade. and  
c) other indications which may be specified by the manufacture. 
 
Each package of pencil shall be legibly and indelibly labelled with the following information; 
a) the name and trade-mark of the manufacturer or the supplier 
b) type and grade of pencils. 
c) quantity of pencils contained therein. 
 
5 7.Sampling   
Sampling for Pencils shall be done as per Annex E 
 
5 8.Testing  
Methods of tests for Pencils shall be as prescribed in the annexes.  
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 CDC 10 (963) DTZS 
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   Annex A 
(normative)   
Determination of blackness of Pencil markings 
 
A1 Apparatus  
A 1.1 Marking of Pencil Lines   
A Whatman drawing paper shall be used. The reflectance value of this paper shall be 79±2. 
  
A l.2 Measurement of Blackness of Pencil Markings   
The apparatus shall consist of a box where light shall be incident on the pencil marking at an  
angle of 45° and the reflected light in a direction perpendicular to the markings shall be received 
by a photocell which shall be connected to a sensitive galvanometer (See Figure 2). The box 
shall be painted from inside with a white paint giving a matt surface. To the output of the photocell 
and in series with the circuit, a suitable opposing electromotive force shall be applied by using a 
dry cell and variable resistance, so that the difference in the reflectance values shall be magnified 
by appropriately controlling the sensitivity of the galvanometer (by using a shunt). The reflectance 
values shall be in the scale of zero reflectance for a perfectly black flat surface and 100 percent 
reflectance for a perfectly white flat surface (MgCO 3 block).  
Thin metal or plastic plates of known reflectance values may also be taken. If three such plates 
are taken with reflectance values approximately in the range 58 to 72 and placed in the box, the 
galvanometer readings may be plotted against the known reflectance values. This graph, which is 
a straight line, may be used to convert the galvanometer readings to reflectance values. 
 CDC 10 (963) DTZS 
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All dimensions in millimetres 
Figure 2 Blackness Indicator 
 
A 1.3 The reflectance measurements shall be made with the help of the apparatus described 
above or any other similar apparatus.  
 
A-2. Procedure  
 
A 2.1 The slip shall be cut square to its length and the end made flat by drawing a few lines, first 
on a sand paper and then on a drawing paper.  
Thirty parallel lines, each of 12 cm length and spaced 1.5 mm from their centres, shall be drawn 
on the drawing paper.  CDC 10 (963) DTZS 
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   A-2.2 The paper with the markings shall be placed in the box and reflectance readings shall be 
taken at three different ' positions of the markings. The mean value of these three readings shall 
be the blackness of the Pencil markings. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 CDC 10 (963) DTZS 
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Annex B 
(normative)   
Determination of friction of Pencil slip 
 
B 1. Apparatus  
 
B 1.1 The apparatus for carrying out this test shall consist of a trolley, 635 mm long and 127 mm wide (see 
Fig. 3). A Whatman drawing paper of the size of the trolley shall be fixed on it. The trolley shall move on two 
rails, 122 cm long, at a speed of about 69 mm per second. The trolley shall be connected by means of a 
string to the rotating pulley of an electric motor.  
 
B l.2 Three pencil holders shall be fixed to a triangular stand such that the distance between any two pencil 
holders as also the height of the stand shall be 50.8 mm. The total weight, including the weight of the 
holders and stand on the three pencil slips, shall be 640±3 g. The load shall be distributed equally on the 
three slips.  
 
B 1.3 A string shall be attached to the Pencil stand and the other end connected to a pointer and weight 
arrangement, so that the force experienced by the stand is measured. The pointer readings shall be 
calibrated as follows:  
The distance between the wooden stand and the torque meter should be kept constant. The thread 
connecting the pencil and the lower end of the pointer shall be disconnected from the pencil stand and 
replaced by a longer thread which can pass over both the pulleys and through a hole in the wooden stand. 
Weights shall be attached to this end of the thread and the pointer readings shall be noted down. A graph of 
the pointer readings and the weight is drawn and may be used to convert the pointer readings to weight in 
grams.  
 
B 2. Procedure  
 
B 2.1 Three pieces from the same slip shall be cut square to their length and fixed in the holders. The upper 
surface of the stand shall be horizontal and 50.8 mm from the ends of the slips. 
  
B.2.2 The Whatman paper shall be fixed to the top of the trolley and the trolley shall be kept on the extreme 
position on the rails towards the pointer scale. The pencil stand shall be kept on the other end of the paper. 
The trolley shall then be pulled. The pencil stand will be dragged along with the trolley due to friction. This 
frictional force shall be balanced by the pointer and weight arrangement. 
 CDC 10 (963) DTZS 
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Figure 3 Apparatus for Measurement of Pencil slip friction 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 CDC 10 (963) DTZS 
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Annex C 
(normative)   
Chemical Inertness of Pencil Markings 
 
When a paper marked with pencil lines is dipped in hydrogen peroxide, it shall not be affected by the latter. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 CDC 10 (963) DTZS 
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Annex D 
(normative)   
Gluing and Warpage of Wood Casing 
 
Finished pencils shall be kept for 48 h in a desiccator filled with water (TZS 59). The casing shall not 
separate. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 CDC 10 (963) DTZS 
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  Annex E 
(normative)   
Sampling 
 
  
E.1 Sampling . 
  
The following sampling procedure shall be applied in determining whether a lot complies with the 
relevant requirements of the specification. The samples so drawn shall be deemed to represent 
the lot for the respective properties.  
  
E-2 From the lot take at containers/packages containers/packages and, after inspecting each of 
them, use one container/ package for testing for compliance with the requirement for shelf life.  
After thoroughly mixing the contents of each of the remaining containers/ packages, by taking an 
approximately equal quantity of product from each container/package.  
 
E-3 Clearly mark the name of the product, the manufacturer’s name or trademark, the batch 
identification and the date of sampling on the sample container/ package.  
  
  
E-4 Compliance with the specification  
  
The lot shall be deemed to comply with the requirements of the specification if, after inspection 
and testing of the samples taken in accordance with D.1, no defective is found.  
  
D-5 Inspection   
Inspect the containers taken in accordance with D.1 for compliance with the requirements in 
clause 4.