DRAFT TANZANIA STANDARD - Shirika la Viwango · 0.2 In the preparation of this draft Tanzania...

DRAFT TANZANIA STANDARD CDC 11(4440)P3

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DRAFT TANZANIA STANDARD

Household plastic ware - Specification

© TBS 2015 — all rights reserved First Edition 2015


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0. FOREWORD

0.1 This Draft Tanzania Standard was developed under the direction of Plastics and Plastic Products

Technical Committee under supervision of the Chemical Division Standards Committee and is in

accordance with the procedures of the Bureau.

0.2 In the preparation of this draft Tanzania Standard assistance was drawn from

GS 613:2007: Plastics – specification for compression - and injection moulded plastic household

wares for food contact applications, published by Ghana Bureau of Standards

The assistance obtained from the above source is hereby acknowledged with thanks

0.3 In reporting the results of analysis of a test if the final value is to be rounded off, it shall be done in

accordance with TZS 4:2009 rounding off numerical values


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1. SCOPE

This Draft Tanzania Standard specifies the requirements, methods of sampling and test for

compression and injection-moulded plastic cups, tumblers, mugs, plates, saucers, trays, bowls and

other similar wares (other than spoons, knives, and forks).

2. NORMATIVE REFERENCES

The following referenced documents are indispensable for the application 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

CDC11 (4437)P3/ISO 472 – Plastics - Vocabulary

TZS 1452-2: Materials and articles in contact with foodstuffs - Plastics - Part 2: Test methods for

overall migration into olive oil by total immersion

ISO 13302 Sensory analysis -- Methods for assessing modifications to the flavour of foodstuffs due

to packaging

ISO 105 A02: Tests for colour fastness -- Part A02: Grey scale for assessing change in colour

IS 9833-2000 List of pigments and colourants for use in plastics in contact with foodstuffs,

pharmaceuticals and drinking water

3. TERMS AND DEFINITIONS

For the purpose of this Draft Tanzania Standard, the following definitions and the definitions given

in CDC11 (4437)P3/ISO 472 shall apply

3.1 Lots

injection - or compression-moulded plastic household wares of the same material, size, shape and

design, manufactured under similar conditions of production in any consignment, shall be grouped

to constitute a lot

3.2 Dimensions

length, width, diameter, thickness and depth of plastic household wares, where appropriate

3.3 Capacity

quantity of water held by the plastic household ware when it is filled

4. REQUIREMENTS

4.1 Material

4.1.1 The household plastic ware shall be made from natural or pigmented plastic materials. Plastic

materials, which can be used for the manufacture of the household plastic wares, are polymethyl

methacrylate, polycarbonate, polypropylene, polyethylene, polystyrene, phenolic, PET and melamine

formaldehyde moulding compounds

4.1.2 The material may contain additives such as impact modifiers and processing aids that improve

the physical and mechanical properties of the material or its weatherability when exposed under normal

service conditions

4.1.3 The material, pigments, masterbatches and other additives shall not include in their composition

any substance, which under conditions of use could be extracted by the contents in quantities sufficient

to cause toxicity. A list of permissible pigments and colorants which can be used is given in IS

9833:2000


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4.2 Construction

4.2.1 The size, shape and design of the household plastic wares shall be as agreed between customer

and supplier. The diameter, length and width of the plastic ware shall be determined in accordance with

the method described in Annex A

4.2.2 For household plastic wares with lids, the lids shall be free from blemishes, which shall preclude

use, and the dimensions of the lids shall be suitable for the ware in question

4.3 Finish

The household plastic wares shall be of uniform finish, and free from defects such as porosity, bubbles,

blisters, flashes, burn marks, mould marks, shrink marks, burrs, distortion, fissures and cracks. They

shall also be substantially free from specks, pinholes and surface bloom. Any sprue shall be neatly

removed by milling or cutting.

4.4 Brimful Capacity

The brimful capacity of household plastic wares (other than plates, saucers and similar shallow wares)

shall be as agreed between customer and supplier and shall be determined in accordance with Annex

B.

4.5 Mass

The mass of each household plastic ware shall be as agreed between customer and supplier.

4.6 Drop impact strength (Drop Test)

Drop impact strength (Drop Test) shall be determined for bowls with lids or similar wares, which are

linked together in a set by means of a flexible strap or any suitable rigid fixture in accordance with Annex

C and shall show no sign of breakage or rupture after the test

4.7 Shock resistance

Household plastic wares which are supplied as single units shall show no sign of breakage when tested

in accordance with Annex D

4.8 Handle strength

Flexible strap or rigid fixture of household plastic which are linked together shall show no sign of rupture

when tested in accordance with Annex E

4.9 Overall migration

The overall migration of the constituents of plastic household wares shall not exceed 60 mg/kg of liquid

food simulant when tested in accordance with TZS 1452-2

4.10 Dimensional stability

Household plastic wares shall show no signs of distortion, crazing, or cracking when tested in

accordance with Annex F

4.11 Relative stain resistance

Household plastic wares shall not be stained considerably when brought into contact with staining

reagents/materials in accordance with Annex G. The ISO Grey Scale is used to evaluate the relative

stain resistance using the 5–step scale or the 9–step scale. (See Table 1). The minimum grey scale

reading shall be 4


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Table 1–Grey Scale and the relative stain resistance

5 - Steps Grey Scale

9 - Steps Grey Scale Relative stain resistance of ware

5

5 Very good

-

4 - 5 Very good/Good

4

4 Good

-

3 - 4 Good/Poor

3

3 Poor

-

2 - 3 Poor/Very poor

2

2 Very poor

-

1 - 2 Very poor/Extremely poor

1

1 Extremely poor

4.12 Odour and Taste

When determined in accordance with Annex H, the plastic household ware shall give no odour or taste

5 PACKING MARKING and LABELLING

5.1 Packing

The household plastic wares shall be packed as agreed between customer and supplier.

5.2 Marking

The following information shall appear in legible and indelible marking on the outside of each household

plastic wares.

a) Name or international code of the plastic material

b) Name of the manufacturer or trade name or trademark, if any.

c) Country of origin.

d) The capacity in millilitres or litres (except for plates, saucers and other similar shallow wares).

5.3 Labelling

In addition to 5.2 bulk packages shall also be marked with the following information:

a) Batch code/number

b) Quantity

6. SAMPLING

6.1 The number of each household plastic ware to be sampled from a lot for ascertaining conformity to

the requirements of this specification shall be in accordance with Table 2.

6.2 The household plastic wares shall be selected at random from the lot. To ensure the randomness

of selection, random number tables shall be used. In case such a table is not available, the following

procedure shall be adopted.

Starting from any household plastic ware in the lot, count them as 1, 2, 3... up to r and so on in one

order, r being the integral part of N/n where N is the total number of the household plastic wares in the


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lot and n the number of wares to be selected. Every rth household plastic ware thus counted shall be

drawn and all such plastic household wares shall constitute the sample.

Table 2–Scale of sampling and permissible number of defects

Lot size

Sample taken from lot Sub – sample size

Number of wares to be selected

Permissible number of defective wares

Up to 50

5 0 4

51 to 100

8 0 4

101 to 150

13 1 4

151 to 300

20 2 4

301 to 500

32 3 4

501 to 1 000

50 5 5

1 001 and above

80 7 5

7 NUMBER OF TEST AND CRITERIA FOR CONFORMITY

7.1 Number of tests

7.1.1 The household plastic wares selected in accordance with 6.2 shall be tested for workmanship and

finish (4.2), construction (4.3), capacity (4.4) and mass (4.5). A plastic household ware failing to satisfy

any one or more of these requirements shall be considered defective. The lot shall be considered as

conforming to the requirements of these characteristics if the number of defective household plastic

wares in the sample is less than or equal to the corresponding number given in column 3 of Table 2.

7.1.2 The lot having been found satisfactory according to 7.1.1 shall be tested for drop impact strength

(4.6), shock resistance (4.7), handle strength (4.8), overall migration (4.9), dimensional stability (4.10),

relative stain resistance (4.11) and odour and taste (4.12). For this purpose, the number of household plastic wares given in the sub - sample shall be selected at random from the lot. These may be selected

from those already examined according to 7.1 and found satisfactory. One of the selected household plastic wares shall be first subjected to drop impact test (4.6) (where applicable) and then tested for

overall migration (4.9), another one for shock resistance (4.7) and dimensional stability (4.10). Another

one shall be first tested for handle strength (4.8) (where applicable) and then tested for relative stain

resistance (4.11), and the last one for odour and taste (4.12).

7.2 criteria for conformity

A household plastic ware failing in any of these requirements shall be considered to be defective. The

lot shall be declared as conforming to the requirements of this specification, if none of the household

plastic wares in the sub-sample is found defective


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8 TEST METHODS

Household plastic wares shall be tested according to validated test method(s), analysis or any other

established methods. Recommended test methods are depicted in Annex A, B, C, D, E, F, G and H


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ANNEX A

(Normative)

DETERMINATION OF SIZE

A.1 Size (as projected area)

(Wares: Plates, saucers, trays and similar wares with circular shape.)

A.1.1 Principle

The size as projected area for wares with circular shape is determined by tracing out the outer periphery

of the ware on paper so that the diameter can be measured and the projected area subsequently

calculated.

A.1.2 Apparatus

A.1.2.1 Large piece of paper

A.1.2.2 Pencil

A.1.2.3 Ruler or calliper

A.1.3 Procedure

Trace out the external circumference of the circular ware on the piece of paper. Determine the diameter

of the circle drawn using the ruler or calliper.

A.1.4 Calculation

The projected area in square centimetres (A) is given by the following formula:

𝐴 =𝜋𝑑2

4

Where

d = Diameter of circle in centimetres


(Wares: Plates, saucers, trays and similar wares with irregular or polygonal shape.)

A.2.1 Principle

The size as projected area for wares with irregular or polygonal shape is determined by finding the

mass of specimen paper of a known area. The outer periphery of the ware is traced out on the paper,

the shape is cut out and the mass determined. The projected area is then calculated

A.2.2 Apparatus

A.2.2.1 Large piece of paper

A.2.2.2 Pencil

A.2.2.3 Sharp knife or any suitable cutting instrument

A.2.2.4 Weighing balance, weighing to the nearest 0.001g

A.2.3 Procedure


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A.2.3.1 Cut out five 10 cm x 10 cm test specimens of the paper to be used for the test from different

areas of the paper. Weigh the test specimens on the balance to the nearest 0,001g. Calculate the

average mass of the test specimens (Ws)

A.2.3.2 Trace out the external border of the ware on the paper from where the specimens used in

A.2.3.1 were cut. Cut out the traced–out shape from the paper and weigh it on the balance (WT)

A.2.4 Calculation

The projected area (A) in square centimetres is given by the following formula:

𝐴 =𝑊𝑇

𝑊𝑆

𝑋 100


(Wares: Plates, saucers, trays and similar wares with rectangular or square shape.)

A.3.1 Principle

The side(s) of the rectangular or square shaped wares are measured using a ruler or calliper and the

area calculated.

A.3.2 Apparatus

Ruler or calliper

A.3.3 Procedure

Measure the length (L) and breadth (B) of the ware using the ruler or calliper.

A.3.4 Calculation

The projected area (A) in square centimetres is given by the following formula

𝐴 = 𝐿𝑥𝐵

Where: L is length

B is breadth


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ANNEX B

(Normative)

DETERMINATION OF CAPACITY

(Wares: Cups, tumblers, mugs, jugs, bowls and similar wares.)

C.1 Method 1

C.1.1 Principle

The ware is weighed, then filled with water to the brim and reweighed. The difference in mass is used

to determine the capacity of the ware.

C.1.2 Apparatus

C.1.2.1 length of thread massed at both ends

C.1.2.2 weighing balance weighing to the nearest 0.01 g.

C.1.3 Procedure

Weigh the empty ware under test, with the massed thread stretched across the top, on the weighing

balance. Fill the ware with water at a temperature of 18 ºC ± 3 ºC to within 3 mm of its brim. Carefully

top up by pipetting water into the ware until the water is seen just touching the thread. Weigh the filled

ware together with the massed thread. The difference in mass is the mass of water in grams, which is

numerically equal to the brimful capacity of the ware in millilitres.

C.2 Method 2

C.2.1 Principle

The ware is filled to the brim with water and the capacity of the ware determined

C.2.2 Apparatus

C.2.2.1 Length of thread massed at both ends

C.2.2.2 Pipettes of various sizes (10 ml, 20 ml, 50 ml, and 100ml)

C.2.2.3 Burette, 50 ml

C-2.3 Procedure

Place the massed thread across the top of the ware whose capacity is to be determined. Fill the ware

with water at room temperature using a pipette to within 3 mm of its brim. Carefully top up the water in

the ware using the burette until the water is seen just touching the thread. The total quantity of water

used to fill the ware is equal to the brimful capacity of the ware in millilitres at that room temperature.


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ANNEX C

(Normative)

DETERMINATION OF DROP IMPACT STRENGTH

(Lunch boxes, canteen sets and similar wares in which bowls with lids, which can be described as units,

are linked together into a set with a flexible strap or rigid fixture.)

D.1 Principle

A quantity of sand equivalent to the total brimful water capacity of the unit, constituting the set is

distributed equally among the units in order to simulate its performance if dropped when in use.

D.2 Apparatus

D.2.1 Flat concrete surface or mild steel sheet

D.2.2 Weighing balance, weighing to the nearest 0.01g.

D.3 Procedure

Weigh each unit of the ware empty. Fill it with water to the brim and reweigh. Record the difference in

mass, which is the brimful water capacity of the unit. Calculate the total brimful capacity of all the units

of the ware. Take the equivalent mass of sand and distribute it equally into the units, which constitute

the set. Seal each unit with a piece of adhesive tape to prevent spillage of the sand out of the units on

impact. Link the ware together into a set with the flexible strap or rigid fixture and drop the ware vertically

and squarely from a height of 1 metre onto the rigid flat surface with the base of the lowest member of

the set hitting it. Change the position of the members of the set till each member of the set has

undergone the same test as the lowest member in the set to hit the hard surface. Examine the ware for

signs of breakage or rupture.


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ANNEX D

(Normative)

DETERMINATION OF SHOCK RESISTANCE

(Wares supplied as single units)

E.1 Principle

A steel ball is dropped from a specified height to the centre of ware which is laid on a flat solid surface

and the ware examined for damage.

E-2 Apparatus

E.2.1 Flat oak board of 3 cm minimum in thickness

E.2.2 Steel ball of 19.05 mm nominal diameter

E.2.3 Metre rule

E.3 Procedure

Lay the ware on the flat oak board or equivalent board horizontally on a flat concrete floor. Drop the

steel ball to approximately the centre of the bottom of the ware from the height given in Table 3. Examine

the ware under test for any damage. The drop height herein means the distance from the lower part of

the steel ball to the surface of the ware under test.

Table 3 – Drop heights for shock resistance

Classification

Drop Height(cm)checked

Round Shapes

Diameter of the rim of the bottom less than 60 mm

20 ± 1

Diameter of the rim of the bottom equal to or more than 60 mm

30 ± 1

Square shape or oval shape or polygonal shape or irregular shape

Equivalent diameter1) of the rim of the bottom less than 60 mm

20 ± 1

Equivalent diameter1) of the rim of the bottom equal to or more than 60 mm

30 ± 1

1) The equivalent diameter is defined as the diameter of the circle having an area equal to the projected area of the rim of the bottom of the plastic household ware. It shall be determined by the method described in A.2 and calculated as given in E.5 below.

E.5 Calculation

The equivalent diameter of the ware with rim of the bottom of square, oval, polygonal or irregular shape

is calculated using the following formula:

𝑑 = √4𝐴

𝜋

Where


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d = Equivalent diameter

A = Projected area

ANNEX E

(Normative)

DETERMINATION OF HANDLE STRENGTH

(Lunch boxes, canteen sets and similar wares in which bowls with lids are linked together into a set with

a flexible strap or rigid fixture.)

F.1 Principle

The ware is massed and hung from a hook fixed on a stable, rigid, vertical surface or on a bar supported

by stable, vertical stands for a fixed period of time and the performance of the flexible strap or rigid

fixture used to hold the units in the set assessed.

F.2 Apparatus

F.2.1 a hook, fixed on a stable, rigid, vertical surface or on a bar supported by stable, vertical stands

F.2.2 Standard weights

F.3 Procedure

Standard weight(s) equal in magnitude to 3 times the total brimful water capacity of all the units in the

set calculated in Annex D are distributed equally into the units of the set. Hung the ware containing the

standard weight(s) by the strap or rigid fixture onto the hook fixed on a stable, rigid, vertical surface or

on the bar supported by stable, vertical stands for 7 days. At the end of the test, examine the flexible

strap or rigid fixture for any sign of breakage or rupture


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ANNEX F

(Normative)

DETERMINATION OF DIMENSIONAL STABILITY

(All wares)

G.1 Principle

The ware is subjected to dry heat and wet heat conditions and the performance assessed under these

conditions.

G.2 Apparatus

G.2.1 Oven - air circulating

G.2.2 Water bath fitted with a thermostat

G.2.3 Timer

G.3 Material

G.3.1 Water

G.4 Procedure

G.4.1 Method 1 - Dry heat test

Place a ware in an air oven maintained at 50ºC ± 2ºC for 6 hours and then cool to room temperature.

Examine the ware for signs of distortion, crazing or cracking

G.4.2 Method 2 - Wet heat test

Immerse the ware in water at a temperature of 70ºC ± 2ºC for 60 ± 5 seconds and then plunge it into

water at a temperature of 21ºC ± 2ºC for 60 ± 5 seconds. Repeat this procedure for 5 consecutive

cycles. Examine the ware for signs of distortion, crazing or cracking.


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ANNEX G

(Normative)

DETERMINATION OF RELATIVE STAIN RESISTANCE

(All wares)

H.1 Principle

Susceptibility of wares to staining by various staining reagents / materials as shown in Table 5 and

determined using the Grey Scale.

H.2 Apparatus

H.2.1 Oven - air circulating

H.2.2 Fine brush

H.2.3 Weighing balance, accurate to 0.1g

H.3 staining materials

H.3.1 Tea - This shall be prepared by pouring 1 litre boiling water onto 8.5 g tea leaves in a hot vessel.

Stir occasionally and decant from the tea leaves after infusion for 5 minutes.

H.3.2 Coffee - This shall be prepared by pouring 1 litre boiling water onto 43.5 g ground coffee in a hot

vessel. Stir occasionally and decant from the ground coffee after infusion for 5 minutes.

H.3.3 Palm oil - Pure, untreated

H.4 Test specimen(s)

The test specimen(s) shall have a flat, smooth surface large enough to permit a test area of 25 mm2 for

visual examination.

H.5 Conditioning

Condition the test specimen(s) at 23ºC ± 5 ºC and 50% ± 2% relative humidity for not less than

40 hours prior to the test in a conditioning atmosphere.

H.6 Procedure

H.6.1 Place the test specimen(s) on a flat surface, and apply a thin film of the liquid staining materials

on them with the fine brush. Place the test specimens in the horizontal position in the oven at a

temperature of 50ºC ± 2ºC for 16 hours. After the oven exposure period, remove any excess staining

material from the surface using a soft dry cloth.

H.6.2 Compare visually the difference between the original specimen and the treated one with the

differences represented by the ISO Grey Scale. The rating for the staining of the specimen is that

number of the Grey Scale which has a perceived colour difference equal in magnitude to the perceived

colour difference between the original and treated specimens. A rating of 5 is given only when there is

no perceived difference between the treated specimen and the original specimen.

Table 5 – Staining material(s) required for test of each ware

Ware Stain Materials

Cups Tumblers Mugs

Tea


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Jugs Saucers

Coffee

Plates Bowls Lunch boxes Canteen sets

Palm oil

Tray Tea Coffee Palm oil

H.6.3 State the rating for the staining according to the ISO Grey Scale and the corresponding relative

stain resistance to the specified staining material(s) in accordance with Table 1.


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ANNEX H

(Normative)

DETERMINATION OF ODOUR AND TASTE

(All wares)

I.1 Principle

The plastic household ware is immersed in a very dilute solution of an organic compound to ascertain

whether the compound can be adsorbed on the surface of the ware to a significant level to impart odour

and/or taste to boiling water poured into it after the immersion.

I.2 Apparatus

I.2.1 Suitable container

I.2.2 Glass plates or watch glasses big enough to cover the mouth of the ware

I.2.3 Stop clock

I.3 Reagent

I.3.1 0.05% sodium dodecylbenzenesulfonate

I.4 Procedure

I.4.1 Immerse 5 pieces of the plastic household ware under test into an aqueous solution of about 0.05

% sodium dodecylbenzenesulfonate. Stir the solution for more than 30 seconds. Remove them and

rinse them thoroughly with distilled water. Fill each of them with boiling water to about 80 % of its

capacity and cover it with a glass plate or watch glass. After 5 min., let 5 members of a test panel take

off the glass plate or watch glasses and ascertain whether there is any odour at the moment when the

glass plates or watch glasses are taken off. Where not less than 3 out of the 5 members of the test

panel declare that there is no odour emanating from the wares under test, the result of the test shall be

"no odour''.

I.4.2 Thirty (30) minutes after the completion of J-4.1, let the five members of the test panel taste the

water to ascertain whether there is any taste. Where not less than 3 out of the 5 members of the test

panel declare that there is no taste in the water in the wares under test, the result of the test shall be

"no taste''

DRAFT TANZANIA STANDARD - Shirika la Viwango · 0.2 In the preparation of this draft Tanzania...

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