HJ/T 411-2007Technical requirement for environmental labeling products - Faucets (English PDF)

3.1 Faucet

Annex A (Informative Annex)

Test and evaluation methods for the precipitation amount of Pb, Cr, Cd

and As in soaking solution of faucets

A.1 Principle

Use the simulated water that contains calcium chloride, sodium bicarbonate

and sodium hypochlorite to soak the contact-part between the interior surface

of the faucet and the water. Adopt inductively coupled plasma inorganic mass

spectrometry (ICP-MS) or graphite furnace atomic absorption spectrometry

(AAS) to determine the heavy metal elements in the soaking solution. After the

measured values of precipitation amount of Pb, Cr, Cd and As are processed

through standardization, compare with the limits listed in Table 1.

A.2 Reagents

A.2.1 Distilled or deionized water. the conductivity is less than 2 µS/cm;

A.2.2 Sodium hypochlorite (chemically pure);

A.2.3 Anhydrous calcium chloride (analytically pure);

A.2.4 Anhydrous sodium bicarbonate (analytically pure);

A.2.5 Pb, Cd, Cr and As standard solutions that meet the instrument conditions;

A.2.6 Concentrated nitric acid (guaranteed reagent).

A.3 Instrument

A.3.1 Graphite furnace atomic absorption spectrometer, inductively coupled

plasma inorganic mass spectrometry;

A.3.2 Commonly-use laboratory glassware;

A.3.3 PVC bottles.

A.4 Sample soaking experiment

A.4.1 Sample preparation and stabilization

A.4.2.2 Preparation of soaking solution (pH = 8.0, hardness of 100mg / L,

available chlorine of 2 mg / L)

Take 25 ml of bicarbonate buffer (A.4.2.1.5), 25 ml of calcium hardness stock

solution (A.4.2.1.4) and the required chlorine stock solution (A.4.2.1.1); dilute

to 1 L with purified water. Prepare the soaking solution required according to

this ratio.

A.4.2.3 Sample soaking

Place the faucet's switch to the fully open position; use the soaking solution to

fill the interior space of the faucet (if there are both hot- and cold-water channels,

both channels shall be included); accurately record the interior space volume

of the faucet according to the amount of the soaking solution. Use a clean cork

or rubber stopper coated with polytetrafluoroethylene film to plug the faucet

ends. There are two methods for the sample soaking experiment. The first

round experiment uses the method (1).

Method (1). soak at (23 ± 2)°C in the dark conditions for (24 ± 0.5) h. Remove

the soaking solution into the PVC bottle. The same faucet shall be

in the soaking experiment for 3 d under the same conditions.

Collect 3 faucet soaking solution samples in total in this experiment.

These samples shall be used to detect the precipitation amount of

Pb, Cr, Cd and As.

Method (2). the evaluation of Pb's precipitation amount shall be conducted with

other elements respectively. When evaluating Pb's precipitation

amount, at least take 3 faucet samples of the same type. When

evaluating other elements, take one faucet sample of the same

type.

The soaking experiment of heavy metal's precipitation amount shall be

conducted at (3 ± 2)°C in the dark conditions for at least 19 d. The first day and

the second day's soak experiments shall be conducted for the interior surface

stabilization of the faucet sample. Separately collect the 16 h soaking solution

of the 3rd, 4th, 5th, 10th, 11th, 12th, 17th and 18th day (e.g. from 16.00 ~ 8.00)

to respectively detect the precipitation amount of Pb. For other-time soaking

solutions, take 2 h as a unit to continuously soak; and use the soaking solution

that is prepared at the same-day to perform the replacement.

For the evaluation of heavy metals other than Pb, it shall take one or multi faucet

k is the statistical parameter depending on the quantity size of samples.

When the number of faucet samples n = 3, k = 2.602 81. k values

corresponding to other sample quantity may be obtained from the following

table.

Table A1 k values used in calculation of statistics Q

Number of

samples k value

Number of

samples k value

3 2.602 81 8 1.359 84

4 1.972 24 9 1.302 34

5 1.697 79 10 1.256 72

6 1.539 87 11 1.219 43

7 1.435 26 12 1.188 24

......