Appendix 1 – Gas-Tight Cabinet test

 The vapour test shall be carried out in a gas-tight cabinet. The dimensions and design of the air tight gas cabinet are not critical, provided the requirements of subparagraphs .6 to .10 below are met. The test gas is designed to simulate the actual crude oil cargo tank environment in ballast condition as well as the vapour conditions of the loaded tank.

• .1 The exposure time is 90 days.

• .2 Testing shall be carried out using duplicate panels; a third panel shall be prepared and stored at ambient conditions to act as a reference panel during final evaluation of the test panels.

• .3 The size of each test panel is 150 mm x 100 mm x 3 mm.

• .4 The panels shall be treated according to the Performance standard table 1, 1.2 and the coating system applied according to table 1, 1.4 and 1.5.

• .5 The zinc silicate shop primer, when used, shall be weathered for at least 2 months and cleaned by low pressure fresh water washing. The exact method of shop primer preparation before being over coated shall be reported, and the judgement issued for that specific system. The reverse side and edges of the test piece shall be coated appropriately, in order not to influence the test results.

• .6 Inside the gas-tight cabinet a trough shall be present. This trough shall be filled with 2 ± 0.2 l of water. The water in the trough shall be drained and renewed prior to each time the test gas is refreshed.

• .7 The vapour spaces inside the gas-tight cabinet shall be filled with a mixture of test gas as per item 5 of the Standard. The cabinet atmosphere shall be maintained over the period of the test. When the gas is outside the scope of the test method, it shall be refreshed. The monitoring frequency and method, and the date and time for refreshing the test gas, shall be in the test report.

• .8 The atmosphere in the test cabinet shall at all times be 95 ± 5% relative humidity.

• .9 Temperature of the test atmosphere shall be 60 ± 3°C.

• .10 A stand for the test panels shall be made of a suitable inert material to hold the panels vertically spaced at least 20 mm between panels. The stand shall be positioned in the cabinet to ensure the lower edge of the panels is at least 200 mm above the height of the water and at least 100 mm from the walls of the cabinet. If two shelves are in the cabinet, care shall be taken to ensure solution does not drip on to the lower panels.

  2.1 Prior to testing, the following measured data of each coating composing the coating system, including the zinc silicate shop primer when used under the coating system, shall be reported:

• .1 infrared (IR) identification of the base and hardener components of the coating;

• .2 specific gravity^footnote of the base and hardener components of the paint; and

• .3 mean dry film thickness (DFT) (by using a template).^footnote

  2.2 After completion of the test duration, the panels shall be removed from the cabinet and rinsed with warm tap water. The panels shall be dried by blotting with absorbent paper and, then, evaluated for rust and blistering within 24 h of the end of the test.

  2.3 After testing, the following measured data shall be reported: blisters and rust.^footnote

  3.1 The test results based on section 2 shall satisfy the following criteria, the poorest performing of the duplicate test panels shall be used in the report:

  3.2 When evaluating test panels, blistering or rusting within 5 mm of the panel edge shall be ignored.

 The test report shall include the following information:

• .1 coating manufacturer's name and manufacturing site;^footnote

• .2 dates of test;

• .3 product name/identification of each coat and, where applicable, zinc silicate shop primer;

• .4 batch numbers of each component of each product;

• .5 details of surface preparation of steel panels, before shop primer application, and treatment of the shop primer before over coating where relevant and at a minimum including the following:

  • .5.1 surface treatment, or treatment of weathered shop primer, and any other important information on treatment influencing the performance; and

  • .5.2 water soluble salt level measured on the steel prior to application of the shop primer;^footnote

• .6 details of coating system, including the following:

  • .6.1 zinc silicate shop primer if relevant, its secondary surface pre-treatment and condition under which applied, weathering period;

  • .6.2 number of coats, including the shop primer, and thickness of each;

  • .6.3 mean dry film thickness (DFT) prior to testing;^footnote

  • .6.4 thinner if used;^footnote

  • .6.5 humidity;^footnote

  • .6.6 air temperature;^footnote and

  • .6.7 steel temperature;^footnote

• .7 details of schedule for refreshing the test gas;

• .8 test results according to section 2; and

• .9 results according to section 3.