Some standard content:
National Standard of the People's Republic of China
Lifejackets for ships
UDC 629.12: 614
GB 4303--84
This standard applies to lifejackets with closed-cell foam plastic as buoyancy material, which can be used for lifesaving of passengers and crew members of various types of ships in inland rivers and oceans.
1 Type
YB type -
- vest type lifejacket, as shown in Figure 1.
1.2YT type - set type lifejacket, as shown in Figure 2. Figure 2
National Bureau of Standards 1984-04-04 Issued
1985-01-01 Implementation
1.3 Marking Example
Vest-type marine life jacket:
Marine life jacket YBGB4303~-84
Suit-type marine life jacket:
Marine life jacket YTGB4303-84
2 Main dimensions
GB4303--84
2.1The main dimensions of YB type marine life jacket are shown in Figures 3 and 4. 230
Note:) The dimensions marked on the figure are the dimensions when no buoyancy material is installed, and the allowable deviation of the dimensions is +3mm. From here on, the collar
②I, II, III, N, V are all buoyancy material bags, and their numbers are consistent with the floating core numbers in Figure 4 (a) and (b). 200
Figure 4 (a)
Belt length 1200
Belt length 3500
Note: The allowable deviation of the floating core size is +3mm. GB4303-84
Figure 4 (b)
2.2 The main dimensions of the YT type marine life jacket are shown in Figures 5 and 6. 520
Long loop (single) length 1750
Fill the core material and sew
Collar cloth length 900
Start tightening the collar here
Fill the core material and sew
GB4303—84
The weight and folded dimensions of the life jacket are shown in Table 1.2.3
YB type life jacket
YT type life jacket
Technical requirements
Marine life jackets shall comply with the requirements of this standard. Width
Marine life jackets shall be orange-yellow and must be worn on both sides. 3.2
Each marine life jacket shall have an instruction manual, which can be worn within 60 seconds after reading without help. 3.3
Weight kg
The wearer shall not be injured when jumping vertically into the water from a height of 4.5m, and the life jacket shall not be displaced or damaged. The distribution of its buoyancy must be able to move the unconscious and exhausted wearer's body to a safe floating position with a backward tilt, an angle of 20° to 50° with the vertical line, and a mouth at least 120mm above the water surface within 5 seconds. 550
GB 4303--84
3.6 The jaw, forehead and armpits near the wearer's purpose should be padded with soft materials to prevent scratches on the human body. 3.7 The straps and connectors should be tested for strength. 3.8 After immersion in fresh water for 24 hours, the loss of its buoyancy shall not exceed 5%. 3.9 It should be able to withstand the combustion resistance test.
3.10 It should be able to withstand the high and low temperature cycle test. 3.11 The front and rear sides of each marine life jacket should have reflective material with an area of not less than 200mm2 on the calm waterline. 3.12 Marine life jackets are made of closed-cell foam plastics, which should be foamed evenly and have basically the same pore size. There should be no decomposition inside and no cracking on the surface. Its physical and chemical properties should meet the requirements of Table 2. Table 2 Physical and chemical properties of closed-cell foam plastics for life jackets Name
Chemical micro-characteristics
Overflow resistance
Buoyancy loss after compression
Dimensional stability
Physical and chemical performance indicators
.55kg/m
No change in 20% sulfuric acid aqueous solution for 24 hours No change in 45% sodium hydroxide aqueous solution for 24 hours Soaking in 3% sodium chloride aqueous solution for 24 hours No change Linear expansion rate is not more than 3.5% when not soaked in diesel for 24 hours No cracking after 8 hours at 30℃
No stickiness after 8 hours at 65℃
0.1 kg / m2
3.13 The density of the cloth used to sew marine life jackets shall be no less than 106 threads per 100mm of warp and weft, and the tensile strength of the cloth (the sample of the cloth is 200×50mm) shall be no less than 80kgf.
3.14 The straps of marine life jackets can be made of soft woven belts or the same fabric as the wrapping cloth. Its tensile strength shall be no less than 90kgf3.15 The tensile strength of the machine-sewn thread used to sew marine life jackets shall be no less than 2kgf. 3.16 Sewing requirements for life jackets
3.16.1 The folding edge of the wrapping cloth shall be no less than 10mm. 3.16.2 The visible seam shall be no less than 3mm from the edge, and the seam shall be uniform, tight and firm, and there shall be no skipped stitches. The density of machine sewing shall not be less than 20 stitches per 50mm, and the end of the seam must be tied back. 3.16.3 The length of the cloth inlaid at the end of the strap should be not less than 30mm. The gauze strap should have not less than 3 stitches. 4 Accessories of life jackets
Each life jacket should be equipped with a corrosion-resistant whistle approved by the Ship Inspection Bureau. 4.1
GB 4303-84
4.2 For life jackets equipped with position lights in accordance with the requirements of the "International Convention for the Safety of Life at Sea", the position lights should also be approved by the Ship Inspection Bureau. 5 Test method
5.1 Buoyancy loss test
Equipment: 1 fresh water tank, 1 industrial scale (sensitivity 0.1kg), 1 non-absorbent net basket, 1 weight (the weight should be such that the net basket with the weight hanging on it does not appear above the water after the life jacket is loaded). Steps:
a. Hang the scale directly above the water tank. Hang the weight in the basket, suspend it in the middle of the water tank, immerse it in water and hang it on the scale, and record the weight W.
b. Put the life jacket in the basket and repeat step a. After the life jacket is immersed in water for 5 minutes, record the weight W2. Keep step b for 24 hours, and then record the weight W3. c.
Calculation formula:
W=WW,
W——the buoyancy of the life jacket, kg
W——the percentage of buoyancy loss (take two significant figures), Wthe weight of the basket and weight in water, kg
W-the weight of the basket, weight and life jacket in water, kg, × 100 % ..
W——the weight of the basket, weight and life jacket in water after being immersed in water for 24 hours, kg. 5.2 Flame resistance test
(1)
(2)
Place a 350×300×60mm test pan in a basically free ventilated place, fill the test pan with 10mm of fresh water, and then pour gasoline to make the total height at least 40mm. Ignite the gasoline and let it burn freely for 30 seconds. At this time, hang the life jacket vertically above the test pan, with its lower end 250mm away from the upper edge of the test pan. After leaving the flame after two seconds, the life jacket should not continue to burn or melt. 5.3 High and low temperature cycle test
The life jacket should be subjected to the ambient temperature of -30±2℃ and 65±2℃ alternately. This alternation is carried out according to the following procedures. a. On the first day, place the life jacket in an environment of 65±2℃, take it out after 8 hours, and place it at room temperature until the next day. b. On the second day, place the life jacket in an environment of -30±2℃, take it out after 8 hours, and place it at room temperature until the third day. c. Completing steps a and b is one cycle, and a total of five cycles are required. After completing the test, the life jacket should show no obvious changes. Cut open the wrapping cloth and take out the buoyancy material. There should be no obvious expansion, contraction, cracking and stickiness.
Strength test of straps and connectors
The straps and connectors sewn on the life jacket must be inspected by the strength test. Hang a 90kg weight on the straps and connectors respectively. After 10 minutes, the straps shall not fall off. The connectors shall not be deformed or cracked. 6 Inspection rules
6.1 The manufacturer shall inspect the buoyancy material, wrapping cloth, straps and stitching in accordance with the requirements of Chapter 3 of this standard. The inspection results shall be submitted to the Ship Inspection Bureau for review.
6.2 Life jackets produced continuously with the same process and the same materials shall not exceed 500 pieces per batch. After each batch of life jackets is manufactured, the Ship Inspection Bureau shall send personnel to inspect together with the factory technical inspection department in accordance with the provisions of Chapter 6, 6.3 to 6.5 of this standard. During the manufacturing period, the Ship Inspection Bureau may also send personnel to the factory for inspection at any time. 6.3 The entire batch of life jackets shall be self-inspected by the factory and accepted after packaging. The number of life jackets sampled for acceptance shall be 2% of each batch, but shall not be less than 2 pieces.
6.4 The acceptance shall include the following items:
6.4.1 Check the dimensions according to the requirements of Chapter 2. GB430384
6.4.2 Check the dimensions according to 3.2, 3.5, 3.11. Check the color, two-sided wearing, buoyancy and reflective materials according to the requirements of Article 3.16. 6.4.3 Check the sewing according to the requirements of Article 3.16. 6.4.4 Check the accessories according to the requirements of Chapter 4. 6.5 If the inspection result is unqualified, double the number should be re-inspected. During the re-inspection, if one result is unqualified, the whole batch should be scrapped. 6.6 When the initial production, production change, production after two years of suspension, and replacement of process and new buoyancy materials, they should be inspected according to the requirements of Chapter 3 of this standard. And they can only be put into production after being reviewed and qualified. 7 Marking, packaging and storage of life jackets
7.1 Each life jacket should have a nameplate including the logo, model, manufacturer's name, product number, year and month of manufacture and the inspection mark of the ship inspection bureau.
7.2 The packaging of life jackets must ensure that they are not eroded by rain and snow. They are not easily damaged during transportation. 7.3 Life jackets should be stored in a clean and dry warehouse and should not be squeezed. 553
A,1 Cutting and pretreatment of samples
GB 4303--84
Appendix A
Test method for closed-cell foam plastics used in life jackets (supplement)
A.1.1 The size of the sample shall be in accordance with the provisions of the test items. If the specified size is not reached, it can be combined. Skin is allowed according to the use. However, it must be a sample made by the same cutting method to complete all the test items. A.1.2 The area of the combined sample is still calculated based on six surface areas. The combined surface is not considered. The combined sample can be tied together with a filament. A.1.3 The cutting of the sample should be representative, and sampling should not be concentrated on a certain part. A.1.4 After the sample is cut, it should be placed in a test environment of 23±2℃ and relative humidity of 65±5% for 4 hours. A.2 Determination of bulk density
Sample size: 50×50×25mm, 3 pieces per group. Instrument: Industrial analytical balance (sensitivity 0.1g), steel ruler (reading value 0.5mm). Steps: Measure the length, width and height of the sample, accurate to 0.5mm. Measure three points each and take the arithmetic mean. Then place the sample in a desiccator (the lower desiccant is calcium chloride), take it out after 4 hours, and weigh it on the balance. Calculation formula:
W-sample bulk density, kg/m2,
W-sample weight, g,
L-sample length, cm,
B-sample width, cmz
H-sample height, cm. The arithmetic mean of the
sample is the test result, take three significant figures. A.3 Determination of chemical stability
A.3.1 Determination of acid, alkali and salt resistance
×1000
（A1）
Take 3 samples of 50×50×25mm in each group. Tie weights to each sample and immerse it in 20% sulfuric acid aqueous solution, 45% caustic soda aqueous solution and 3% sodium chloride aqueous solution at 23±2℃. Take out the sample after 24 hours and check whether the sample has changed. A.3.2 Determination of oil resistance
Sample size: 100×100×25mm. 3 samples in each group. Instrument: Vernier caliper, oil bath device.
Steps: After measuring the size according to Figure A1, tie weights to each sample and immerse it in diesel oil at an oil temperature of 23±2℃. Take it out after 24 hours. Wipe the surface with filter paper and measure the size accurately to 0.1mm. Calculation formula:
(B); -(B。);
(B。);
(Lt)- (Lo)i × 100.
（A3）
α is the larger of α and α.
Linear expansion rate of a sample, %,
Where: α -
GB 4303-84
Linear expansion rate of a sample in B direction, %,
Linear expansion rate of a sample in L direction, %,
（Bt）—The maximum change in the B dimension of the sample after immersion, mm, (Lt): The maximum change in the L dimension of the sample after immersion, mm (Bo);
The reference number of the maximum change in the B dimension of the sample, mm, (Lo);
The reference number of the maximum change in the L dimension of the sample, mm. The arithmetic mean of the samples is the test result, rounded to two significant figures. A.4 Determination of heat resistance
A.4.1 Determination of heat resistance
Specimen size: 100×100×25mm, 3 pieces per group. Instrument: constant temperature box, steel ruler.
(Ls)
Steps: Place the specimens flat on the metal mesh in a constant temperature box at 65±2℃, with the distance between the specimens not less than 25mm. Take them out after 8 hours. Check that their appearance should not be sticky.
A.4.2 Determination of cold resistance
Specimen size: 100×100×25mm, 3 pieces per group. Instrument: low temperature refrigerator, steel ruler.
Steps: Place the specimens in a low temperature refrigerator at -30±2℃, take them out after 8 hours, and check that their appearance should not have cracks. A.5 Determination of water absorption
Specimen size: 100×100×25mm, 3 pieces per group. Instruments: analytical balance (sensitivity 0.0001g), vernier caliper. Steps: a. Measure the size of the sample to an accuracy of 1 mm. Measure three points each and calculate the arithmetic mean. b. Place the sample in a desiccator filled with calcium chloride, take it out after 24 hours and weigh it on a balance. Then immerse the sample in a glass container filled with distilled water to a depth of 50mm, the water temperature is 25±2℃, and take it out after 24 hours. Use filter paper to absorb the surface moisture 555
GB 4303-84
and weigh it. The removal, absorbing and weighing of the sample should be completed within 3 minutes. Calculation formula:
Where: Ws-
—water absorption per unit area, kg/m2,
G1—weight of the sample before immersion in water, g,
—weight of the sample after immersion in water, g,
S—total surface area of the sample, cm2
The arithmetic mean of the sample is the test result, take two significant figures. A.6 Determination of buoyancy loss after compression
Sample size: 100×100×75mm, 3 pieces per group. X 10
Instrument: pharmaceutical balance (sensitivity 1g); 120×120mm rigid flat plate-block and a weight (total weight 88±1kg). Steps: a. Measure the buoyancy of the sample according to the method in Section 5.1 of Chapter 5 (change the scale to a pharmaceutical balance). b. Place the sample flat on a smooth and hard surface. Make one 100×100mm surface of the sample face upward. Place a flat plate on the sample and press a heavy object on the plate. Take out the sample after one hour, measure its buoyancy again after the sample recovers for 5 minutes, and calculate the buoyancy loss.
Calculation formula:
W—the buoyancy of the sample after compression, g, Wsy the percentage of buoyancy loss after compression, %. The calculated average value of WW.
sample is the test result, take two significant figures. A.7 Dimensional stability
Sample size: 100×100×25mm, 3 pieces per group. Instrument: Constant temperature blast drying oven, constant temperature low temperature refrigerator, vernier caliper. X100
Steps: a. Measure the size of the sample according to the position A1 in Figure (accurate to o.1mm). b. Adjust the drying oven temperature to 65±2℃ and the refrigerator temperature to -30±2℃ respectively. (A5)
c. Place the sample flat in a drying oven and refrigerator, with the distance between the samples not less than 20 mm, and take it out after six hours of constant temperature. Place it at room temperature for 1 hour, and then measure the size of the part A1 in Figure. Calculation formula:
X is the larger number between X and X,.
In the formula: X is the rate of change of sample dimension, %, XB is the rate of change of B dimension, %,
XL is the rate of change of L dimension, %
(B.):-(Bo)i× 100
(Lt);- (Lo)ix
(L.)
(A6)
(A 7)
GB 4303--84
(B,): the B dimension of the sample with the largest change after constant temperature, mm, (L,);
the L dimension of the sample with the largest change after constant temperature, mm; (B.)—
the reference number of the B dimension of the sample with the largest change, mm (L.)i
the reference number of the L dimension of the sample with the largest change, mm. The arithmetic mean of the samples is the test result, and two significant figures are taken. Additional Notes:
This standard was proposed by China State Shipbuilding Corporation and is under the jurisdiction of Guangzhou Shipyard. This standard was drafted by Tianjin No. 15 Plastic Products Factory and Tianjin Ship Inspection Office. The main drafters of this standard are Gu Songzhen and Xi Xueshi.5 If the inspection result is unqualified, double the quantity should be taken for re-inspection. If one result is unqualified during the re-inspection, the entire batch should be scrapped. 6.6 When initially put into production, switched production, stopped production for two years for re-production, and when replacing processes and new buoyancy materials, they should be inspected in accordance with the requirements of Chapter 3 of this standard. They can only be put into production after being reviewed and qualified. 7 Marking, packaging and storage of life jackets
7.1 Each life jacket should have a nameplate including the logo, model, manufacturer's name, product number, year and month of manufacture and the inspection mark of the Ship Inspection Bureau.
7.2 The packaging of life jackets must ensure that they are not corroded by rain and snow. They are not easily damaged during transportation. 7.3 Life jackets should be stored in a clean and dry warehouse and should not be squeezed. 553
A,1 Cutting and pretreatment of samples
GB 4303--84
Appendix A
Test method for closed-cell foam plastics used in life jackets (supplement)
A.1.1 The size of the sample shall be in accordance with the provisions of the test items. If the specified size is not reached, it can be combined. Skin is allowed according to the use. However, it must be a sample made by the same cutting method to complete all the test items. A.1.2 The area of the combined sample is still calculated based on six surface areas. The combined surface is not considered. The combined sample can be tied together with a filament. A.1.3 The cutting of the sample should be representative, and sampling should not be concentrated on a certain part. A.1.4 After the sample is cut, it should be placed in a test environment of 23±2℃ and relative humidity of 65±5% for 4 hours. A.2 Determination of bulk density
Sample size: 50×50×25mm, 3 pieces per group. Instrument: Industrial analytical balance (sensitivity 0.1g), steel ruler (reading value 0.5mm). Steps: Measure the length, width and height of the sample, accurate to 0.5mm. Measure three points each and take the arithmetic mean. Then place the sample in a desiccator (the lower desiccant is calcium chloride), take it out after 4 hours, and weigh it on the balance. Calculation formula:
W-sample bulk density, kg/m2,
W-sample weight, g,
L-sample length, cm,
B-sample width, cmz
H-sample height, cm. The arithmetic mean of the
sample is the test result, take three significant figures. A.3 Determination of chemical stability
A.3.1 Determination of acid, alkali and salt resistance
×1000
（A1）
Take 3 samples of 50×50×25mm in each group. Tie weights to each sample and immerse it in 20% sulfuric acid aqueous solution, 45% caustic soda aqueous solution and 3% sodium chloride aqueous solution at 23±2℃. Take out the sample after 24 hours and check whether the sample has changed. A.3.2 Determination of oil resistance
Sample size: 100×100×25mm. 3 samples in each group. Instrument: Vernier caliper, oil bath device.
Steps: After measuring the size according to Figure A1, tie weights to each sample and immerse it in diesel oil at an oil temperature of 23±2℃. Take it out after 24 hours. Wipe the surface with filter paper and measure the size accurately to 0.1mm. Calculation formula:
(B); -(B。);
(B。);
(Lt)- (Lo)i × 100.
（A3）
α is the larger of α and α.
Linear expansion rate of a sample, %,
Where: α -
GB 4303-84
Linear expansion rate of a sample in B direction, %,
Linear expansion rate of a sample in L direction, %,
（Bt）—The maximum change in the B dimension of the sample after immersion, mm, (Lt): The maximum change in the L dimension of the sample after immersion, mm (Bo);
The reference number of the maximum change in the B dimension of the sample, mm, (Lo);
The reference number of the maximum change in the L dimension of the sample, mm. The arithmetic mean of the samples is the test result, rounded to two significant figures. A.4 Determination of heat resistance
A.4.1 Determination of heat resistance
Specimen size: 100×100×25mm, 3 pieces per group. Instrument: constant temperature box, steel ruler.
(Ls)
Steps: Place the specimens flat on the metal mesh in a constant temperature box at 65±2℃, with the distance between the specimens not less than 25mm. Take them out after 8 hours. Check that their appearance should not be sticky.
A.4.2 Determination of cold resistance
Specimen size: 100×100×25mm, 3 pieces per group. Instrument: low temperature refrigerator, steel ruler.
Steps: Place the specimens in a low temperature refrigerator at -30±2℃, take them out after 8 hours, and check that their appearance should not have cracks. A.5 Determination of water absorption
Specimen size: 100×100×25mm, 3 pieces per group. Instruments: analytical balance (sensitivity 0.0001g), vernier caliper. Steps: a. Measure the sample size to an accuracy of 1 mm. Measure three points each and calculate the arithmetic mean. b. Place the sample in a desiccator filled with calcium chloride, take it out after 24 hours and weigh it on a balance. Then immerse the sample in a glass container filled with distilled water to a depth of 50mm, the water temperature is 25±2℃, and take it out after 24 hours. Use filter paper to absorb the surface moisture 555
GB 4303-84
and weigh it. The removal, absorbing and weighing of the sample should be completed within 3 minutes. Calculation formula:
Where: Ws-
—water absorption per unit area, kg/m2,
G1—weight of the sample before immersion in water, g,
—weight of the sample after immersion in water, g,
S—total surface area of the sample, cm2
The arithmetic mean of the sample is the test result, take two significant figures. A.6 Determination of buoyancy loss after compression
Sample size: 100×100×75mm, 3 pieces per group. X 10
Instrument: pharmaceutical balance (sensitivity 1g); 120×120mm rigid flat plate-block and a weight (total weight 88±1kg). Steps: a. Measure the buoyancy of the sample according to the method in Section 5.1 of Chapter 5 (change the scale to a pharmaceutical balance). b. Place the sample flat on a smooth and hard surface. Make one 100×100mm surface of the sample face upward. Place a flat plate on the sample and press a heavy object on the plate. Take out the sample after one hour, measure its buoyancy again after the sample recovers for 5 minutes, and calculate the buoyancy loss.
Calculation formula:
W—the buoyancy of the sample after compression, g, Wsy the percentage of buoyancy loss after compression, %. The calculated average value of WW.
sample is the test result, take two significant figures. A.7 Dimensional stability
Sample size: 100×100×25mm, 3 pieces per group. Instrument: Constant temperature blast drying oven, constant temperature low temperature refrigerator, vernier caliper. X100
Steps: a. Measure the size of the sample according to the position A1 in Figure (accurate to o.1mm). b. Adjust the drying oven temperature to 65±2℃ and the refrigerator temperature to -30±2℃ respectively. (A5)
c. Place the sample flat in a drying oven and refrigerator, with the distance between the samples not less than 20 mm, and take it out after six hours of constant temperature. Place it at room temperature for 1 hour, and then measure the size of the part A1 in Figure. Calculation formula:
X is the larger number between X and X,.
In the formula: X is the rate of change of sample dimension, %, XB is the rate of change of B dimension, %,
XL is the rate of change of L dimension, %
(B.):-(Bo)i× 100
(Lt);- (Lo)ix
(L.)
(A6)
(A 7)
GB 4303--84
(B,): the B dimension of the sample with the largest change after constant temperature, mm, (L,);
the L dimension of the sample with the largest change after constant temperature, mm; (B.)—
the reference number of the B dimension of the sample with the largest change, mm (L.)i
the reference number of the L dimension of the sample with the largest change, mm. The arithmetic mean of the samples is the test result, and two significant figures are taken. Additional Notes:
This standard was proposed by China State Shipbuilding Corporation and is under the jurisdiction of Guangzhou Shipyard. This standard was drafted by Tianjin No. 15 Plastic Products Factory and Tianjin Ship Inspection Office. The main drafters of this standard are Gu Songzhen and Xi Xueshi.5 If the inspection result is unqualified, double the quantity should be taken for re-inspection. If one result is unqualified during the re-inspection, the entire batch should be scrapped. 6.6 When initially put into production, switched production, stopped production for two years for re-production, and when replacing processes and new buoyancy materials, they should be inspected in accordance with the requirements of Chapter 3 of this standard. They can only be put into production after being reviewed and qualified. 7 Marking, packaging and storage of life jackets
7.1 Each life jacket should have a nameplate including the logo, model, manufacturer's name, product number, year and month of manufacture and the inspection mark of the Ship Inspection Bureau.
7.2 The packaging of life jackets must ensure that they are not corroded by rain and snow. They are not easily damaged during transportation. 7.3 Life jackets should be stored in a clean and dry warehouse and should not be squeezed. 553
A,1 Cutting and pretreatment of samples
GB 4303--84
Appendix A
Test method for closed-cell foam plastics used in life jackets (supplement)
A.1.1 The size of the sample shall be in accordance with the provisions of the test items. If the specified size is not reached, it can be combined. Skin is allowed according to the use. However, it must be a sample made by the same cutting method to complete all the test items. A.1.2 The area of the combined sample is still calculated based on six surface areas. The combined surface is not considered. The combined sample can be tied together with a filament. A.1.3 The cutting of the sample should be representative, and sampling should not be concentrated on a certain part. A.1.4 After the sample is cut, it should be placed in a test environment of 23±2℃ and relative humidity of 65±5% for 4 hours. A.2 Determination of bulk density
Sample size: 50×50×25mm, 3 pieces per group. Instrument: Industrial analytical balance (sensitivity 0.1g), steel ruler (reading value 0.5mm). Steps: Measure the length, width and height of the sample, accurate to 0.5mm. Measure three points each and take the arithmetic mean. Then place the sample in a desiccator (the lower desiccant is calcium chloride), take it out after 4 hours, and weigh it on the balance. Calculation formula:
W-sample bulk density, kg/m2,
W-sample weight, g,
L-sample length, cm,
B-sample width, cmz
H-sample height, cm. The arithmetic mean of the bzxZ.net
sample is the test result, take three significant figures. A.3 Determination of chemical stability
A.3.1 Determination of acid, alkali and salt resistance
×1000
（A1）
Take 3 samples of 50×50×25mm in each group. Tie weights to each sample and immerse it in 20% sulfuric acid aqueous solution, 45% caustic soda aqueous solution and 3% sodium chloride aqueous solution at 23±2℃. Take out the sample after 24 hours and check whether the sample has changed. A.3.2 Determination of oil resistance
Sample size: 100×100×25mm. 3 samples in each group. Instrument: Vernier caliper, oil bath device.
Steps: After measuring the size according to Figure A1, tie weights to each sample and immerse it in diesel oil at an oil temperature of 23±2℃. Take it out after 24 hours. Wipe the surface with filter paper and measure the size accurately to 0.1mm. Calculation formula:
(B); -(B。);
(B。);
(Lt)- (Lo)i × 100.
（A3）
α is the larger of α and α.
Linear expansion rate of a sample, %,
Where: α -
GB 4303-84
Linear expansion rate of a sample in B direction, %,
Linear expansion rate of a sample in L direction, %,
（Bt）—The maximum change in the B dimension of the sample after immersion, mm, (Lt): The maximum change in the L dimension of the sample after immersion, mm (Bo);
The reference number of the maximum change in the B dimension of the sample, mm, (Lo);
The reference number of the maximum change in the L dimension of the sample, mm. The arithmetic mean of the samples is the test result, rounded to two significant figures. A.4 Determination of heat resistance
A.4.1 Determination of heat resistance
Specimen size: 100×100×25mm, 3 pieces per group. Instrument: constant temperature box, steel ruler.
(Ls)
Steps: Place the specimens flat on the metal mesh in a constant temperature box at 65±2℃, with the distance between the specimens not less than 25mm. Take them out after 8 hours. Check that their appearance should not be sticky.
A.4.2 Determination of cold resistance
Specimen size: 100×100×25mm, 3 pieces per group. Instrument: low temperature refrigerator, steel ruler.
Steps: Place the specimens in a low temperature refrigerator at -30±2℃, take them out after 8 hours, and check that their appearance should not have cracks. A.5 Determination of water absorption
Specimen size: 100×100×25mm, 3 pieces per group. Instruments: analytical balance (sensitivity 0.0001g), vernier caliper. Steps: a. Measure the size of the sample to an accuracy of 1 mm. Measure three points each and calculate the arithmetic mean. b. Place the sample in a desiccator filled with calcium chloride, take it out after 24 hours and weigh it on a balance. Then immerse the sample in a glass container filled with distilled water to a depth of 50mm, the water temperature is 25±2℃, and take it out after 24 hours. Use filter paper to absorb the surface moisture 555
GB 4303-84
and weigh it. The removal, absorbing and weighing of the sample should be completed within 3 minutes. Calculation formula:
Where: Ws-
—water absorption per unit area, kg/m2,
G1—weight of the sample before immersion in water, g,
—weight of the sample after immersion in water, g,
S—total surface area of the sample, cm2
The arithmetic mean of the sample is the test result, take two significant figures. A.6 Determination of buoyancy loss after compression
Sample size: 100×100×75mm, 3 pieces per group. X 10
Instrument: pharmaceutical balance (sensitivity 1g); 120×120mm rigid flat plate-block and a weight (total weight 88±1kg). Steps: a. Measure the buoyancy of the sample according to the method in Section 5.1 of Chapter 5 (change the scale to a pharmaceutical balance). b. Place the sample flat on a smooth and hard surface. Make one 100×100mm surface of the sample face upward. Place a flat plate on the sample and press a heavy object on the plate. Take out the sample after one hour, measure its buoyancy again after the sample recovers for 5 minutes, and calculate the buoyancy loss.
Calculation formula:
W—the buoyancy of the sample after compression, g, Wsy the percentage of buoyancy loss after compression, %. The calculated average value of WW.
sample is the test result, take two significant figures. A.7 Dimensional stability
Sample size: 100×100×25mm, 3 pieces per group. Instrument: Constant temperature blast drying oven, constant temperature low temperature refrigerator, vernier caliper. X100
Steps: a. Measure the size of the sample according to the position A1 in Figure (accurate to o.1mm). b. Adjust the drying oven temperature to 65±2℃ and the refrigerator temperature to -30±2℃ respectively. (A5)
c. Place the sample flat in a drying oven and refrigerator, with the distance between the samples not less than 20 mm, and take it out after six hours of constant temperature. Place it at room temperature for 1 hour, and then measure the size of the part A1 in Figure. Calculation formula:
X is the larger number between X and X,.
In the formula: X is the rate of change of sample dimension, %, XB is the rate of change of B dimension, %,
XL is the rate of change of L dimension, %
(B.):-(Bo)i× 100
(Lt);- (Lo)ix
(L.)
(A6)
(A 7)
GB 4303--84
(B,): the B dimension of the sample with the largest change after constant temperature, mm, (L,);
the L dimension of the sample with the largest change after constant temperature, mm; (B.)—
the reference number of the B dimension of the sample with the largest change, mm (L.)i
the reference number of the L dimension of the sample with the largest change, mm. The arithmetic mean of the samples is the test result, and two significant figures are taken. Additional Notes:
This standard was proposed by China State Shipbuilding Corporation and is under the jurisdiction of Guangzhou Shipyard. This standard was drafted by Tianjin No. 15 Plastic Products Factory and Tianjin Ship Inspection Office. The main drafters of this standard are Gu Songzhen and Xi Xueshi.2 The packaging of life jackets must ensure that they are not corroded by rain and snow. They are not easily damaged during transportation. 7.3 Life jackets should be stored in a clean and dry warehouse and should not be squeezed. 553
A,1 Cutting and pretreatment of samples
GB 4303--84
Appendix A
Test method for closed-cell foam plastics used in life jackets (supplement)
A.1.1 The size of the sample shall be implemented in accordance with the provisions of the measurement items. If the specified size is not reached, it can be combined. Skin is allowed according to the use situation. However, it must be a sample with the same cutting method to complete all test items. A.1.2 The area of the combined sample is still calculated based on six surface areas. The combined surface is not considered. The combined sample can be tied together with a filament. A.1.3 The cutting of the sample should be representative, and sampling should not be concentrated on a certain part. A.1.4 After the sample is cut, it should be placed in a test environment of 23±2℃ and relative humidity of 65±5% for 4 hours. A.2 Determination of bulk density
Sample size: 50×50×25mm, 3 pieces per group. Instrument: industrial analytical balance (sensitivity 0.1g), steel ruler (reading value 0.5mm). Steps: Measure the length, width and height of the sample to an accuracy of 0.5mm. Measure three points each and take the arithmetic mean. Then place the sample in a desiccator (the lower desiccant is calcium chloride), take it out after 4 hours, and weigh it on the balance. Calculation formula:
W—sample bulk density, kg/m2,
W—sample weight, g,
L—sample length, cm,
B—sample width, cmz
H—sample height, cm. The arithmetic mean of the sample is the test result, with three significant figures. A.3 Determination of chemical stability
A.3.1 Determination of acid, alkali and salt resistance
×1000
（A1）
Take 3 samples of 50×50×25mm in each group. Tie weights to each sample and immerse it in 20% sulfuric acid aqueous solution, 45% caustic soda aqueous solution and 3% sodium chloride aqueous solution at 23±2℃. Take out the sample after 24 hours and check whether the sample has changed. A.3.2 Determination of oil resistance
Sample size: 100×100×25mm. 3 samples in each group. Instrument: Vernier caliper, oil bath device.
Steps: After measuring the size according to Figure A1, tie weights to each sample and immerse it in diesel oil at an oil temperature of 23±2℃. Take it out after 24 hours. Wipe the surface with filter paper and measure the size accurately to 0.1mm. Calculation formula:
(B); -(B。);
(B。);
(Lt)- (Lo)i × 100.
（A3）
α is the larger of α and α.
Linear expansion rate of a sample, %,
Where: α -
GB 4303-84
Linear expansion rate of a sample in B direction, %,
Linear expansion rate of a sample in L direction, %,
（Bt）—The maximum change in the B dimension of the sample after immersion, mm, (Lt): The maximum change in the L dimension of the sample after immersion, mm (Bo);
The reference number of the maximum change in the B dimension of the sample, mm, (Lo);
The reference number of the maximum change in the L dimension of the sample, mm. The arithmetic mean of the samples is the test result, rounded to two significant figures. A.4 Determination of heat resistance
A.4.1 Determination of heat resistance
Specimen size: 100×100×25mm, 3 pieces per group. Instrument: constant temperature box, steel ruler.
(Ls)
Steps: Place the specimens flat on the metal mesh in a constant temperature box at 65±2℃, with the distance between the specimens not less than 25mm. Take them out after 8 hours. Check that their appearance should not be sticky.
A.4.2 Determination of cold resistance
Specimen size: 100×100×25mm, 3 pieces per group. Instrument: low temperature refrigerator, steel ruler.
Steps: Place the specimens in a low temperature refrigerator at -30±2℃, take them out after 8 hours, and check that their appearance should not have cracks. A.5 Determination of water absorption
Specimen size: 100×100×25mm, 3 pieces per group. Instruments: analytical balance (sensitivity 0.0001g), vernier caliper. Steps: a. Measure the size of the sample to an accuracy of 1 mm. Measure three points each and calculate the arithmetic mean. b. Place the sample in a desiccator filled with calcium chloride, take it out after 24 hours and weigh it on a balance. Then immerse the sample in a glass container filled with distilled water to a depth of 50mm, the water temperature is 25±2℃, and take it out after 24 hours. Use filter paper to absorb the surface moisture 555
GB 4303-84
and weigh it. The removal, absorbing and weighing of the sample should be completed within 3 minutes. Calculation formula:
Where: Ws-
—water absorption per unit area, kg/m2,
G1—weight of the sample before immersion in water, g,
—weight of the sample after immersion in water, g,
S—total surface area of the sample, cm2
The arithmetic mean of the sample is the test result, take two significant figures. A.6 Determination of buoyancy loss after compression
Sample size: 100×100×75mm, 3 pieces per group. X 10
Instrument: pharmaceutical balance (sensitivity 1g); 120×120mm rigid flat plate-block and a weight (total weight 88±1kg). Steps: a. Measure the buoyancy of the sample according to the method in Section 5.1 of Chapter 5 (change the scale to a pharmaceutical balance). b. Place the sample flat on a smooth and hard surface. Make one 100×100mm surface of the sample face upward. Place a flat plate on the sample and press a heavy object on the plate. Take out the sample after one hour, measure its buoyancy again after the sample recovers for 5 minutes, and calculate the buoyancy loss.
Calculation formula:
W—the buoyancy of the sample after compression, g, Wsy the percentage of buoyancy loss after compression, %. The calculated average value of WW.
sample is the test result, take two significant figures. A.7 Dimensional stability
Sample size: 100×100×25mm, 3 pieces per group. Instrument: Constant temperature blast drying oven, constant temperature low temperature refrigerator, vernier caliper. X100
Steps: a. Measure the size of the sample according to the position A1 in Figure (accurate to o.1mm). b. Adjust the drying oven temperature to 65±2℃ and the refrigerator temperature to -30±2℃ respectively. (A5)
c. Place the sample flat in a drying oven and refrigerator, with the distance between the samples not less than 20 mm, and take it out after six hours of constant temperature. Place it at room temperature for 1 hour, and then measure the size of the part A1 in Figure. Calculation formula:
X is the larger number between X and X,.
In the formula: X is the rate of change of sample dimension, %, XB is the rate of change of B dimension, %,
XL is the rate of change of L dimension, %
(B.):-(Bo)i× 100
(Lt);- (Lo)ix
(L.)
(A6)
(A 7)
GB 4303--84
(B,): the B dimension of the sample with the largest change after constant temperature, mm, (L,);
the L dimension of the sample with the largest change after constant temperature, mm; (B.)—
the reference number of the B dimension of the sample with the largest change, mm (L.)i
the reference number of the L dimension of the sample with the largest change, mm. The arithmetic mean of the samples is the test result, and two significant figures are taken. Additional Notes:
This standard was proposed by China State Shipbuilding Corporation and is under the jurisdiction of Guangzhou Shipyard. This standard was drafted by Tianjin No. 15 Plastic Products Factory and Tianjin Ship Inspection Office. The main drafters of this standard are Gu Songzhen and Xi Xueshi.2 The packaging of life jackets must ensure that they are not corroded by rain and snow. They are not easily damaged during transportation. 7.3 Life jackets should be stored in a clean and dry warehouse and should not be squeezed. 553
A,1 Cutting and pretreatment of samples
GB 4303--84
Appendix A
Test method for closed-cell foam plastics used in life jackets (supplement)
A.1.1 The size of the sample shall be implemented in accordance with the provisions of the measurement items. If the specified size is not reached, it can be combined. Skin is allowed according to the use situation. However, it must be a sample with the same cutting method to complete all test items. A.1.2 The area of the combined sample is still calculated based on six surface areas. The combined surface is not considered. The combined sample can be tied together with a filament. A.1.3 The cutting of the sample should be representative, and sampling should not be concentrated on a certain part. A.1.4 After the sample is cut, it should be placed in a test environment of 23±2℃ and relative humidity of 65±5% for 4 hours. A.2 Determination of bulk density
Sample size: 50×50×25mm, 3 pieces per group. Instrument: industrial analytical balance (sensitivity 0.1g), steel ruler (reading value 0.5mm). Steps: Measure the length, width and height of the sample to an accuracy of 0.5mm. Measure three points each and take the arithmetic mean. Then place the sample in a desiccator (the lower desiccant is calcium chloride), take it out after 4 hours, and weigh it on the balance. Calculation formula:
W—sample bulk density, kg/m2,
W—sample weight, g,
L—sample length, cm,
B—sample width, cmz
H—sample height, cm. The arithmetic mean of the sample is the test result, with three significant figures. A.3 Determination of chemical stability
A.3.1 Determination of acid, alkali and salt resistance
×1000
（A1）
Take 3 samples of 50×50×25mm in each group. Tie weights to each sample and immerse it in 20% sulfuric acid aqueous solution, 45% caustic soda aqueous solution and 3% sodium chloride aqueous solution at 23±2℃. Take out the sample after 24 hours and check whether the sample has changed. A.3.2 Determination of oil resistance
Sample size: 100×100×25mm. 3 samples in each group. Instrument: Vernier caliper, oil bath device.
Steps: After measuring the size according to Figure A1, tie weights to each sample and immerse it in diesel oil at an oil temperature of 23±2℃. Take it out after 24 hours. Wipe the surface with filter paper and measure the size accurately to 0.1mm. Calculation formula:
(B); -(B。);
(B。);
(Lt)- (Lo)i × 100.
（A3）
α is the larger of α and α.
Linear expansion rate of a sample, %,
Where: α -
GB 4303-84
Linear expansion rate of a sample in B direction, %,
Linear expansion rate of a sample in L direction, %,
（Bt）—The maximum change in the B dimension of the sample after immersion, mm, (Lt): The maximum change in the L dimension of the sample after immersion, mm (Bo);
The reference number of the maximum change in the B dimension of the sample, mm, (Lo);
The reference number of the maximum change in the L dimension of the sample, mm. The arithmetic mean of the samples is the test result, rounded to two significant figures. A.4 Determination of heat resistance
A.4.1 Determination of heat resistance
Specimen size: 100×100×25mm, 3 pieces per group. Instrument: constant temperature box, steel ruler.
(Ls)
Steps: Place the specimens flat on the metal mesh in a constant temperature box at 65±2℃, with the distance between the specimens not less than 25mm. Take them out after 8 hours. Check that their appearance should not be sticky.
A.4.2 Determination of cold resistance
Specimen size: 100×100×25mm, 3 pieces per group. Instrument: low temperature refrigerator, steel ruler.
Steps: Place the specimens in a low temperature refrigerator at -30±2℃, take them out after 8 hours, and check that their appearance should not have cracks. A.5 Determination of water absorption
Specimen size: 100×100×25mm, 3 pieces per group. Instruments: analytical balance (sensitivity 0.0001g), vernier caliper. Steps: a. Measure the size of the sample to an accuracy of 1 mm. Measure three points each and calculate the arithmetic mean. b. Place the sample in a desiccator filled with calcium chloride, take it out after 24 hours and weigh it on a balance. Then immerse the sample in a glass container filled with distilled water to a depth of 50mm, the water temperature is 25±2℃, and take it out after 24 hours. Use filter paper to absorb the surface moisture 555
GB 4303-84
and weigh it. The removal, absorbing and weighing of the sample should be completed within 3 minutes. Calculation formula:
Where: Ws-
—water absorption per unit area, kg/m2,
G1—weight of the sample before immersion in water, g,
—weight of the sample after immersion in water, g,
S—total surface area of the sample, cm2
The arithmetic mean of the sample is the test result, take two significant figures. A.6 Determination of buoyancy loss after compression
Sample size: 100×100×75mm, 3 pieces per group. X 10
Instrument: pharmaceutical balance (sensitivity 1g); 120×120mm rigid flat plate-block and a weight (total weight 88±1kg). Steps: a. Measure the buoyancy of the sample according to the method in Section 5.1 of Chapter 5 (change the scale to a pharmaceutical balance). b. Place the sample flat on a smooth and hard surface. Make one 100×100mm surface of the sample face upward. Place a flat plate on the sample and press a heavy object on the plate. Take out the sample after one hour, measure its buoyancy again after the sample recovers for 5 minutes, and calculate the buoyancy loss.
Calculation formula:
W—the buoyancy of the sample after compression, g, Wsy the percentage of buoyancy loss after compression, %. The calculated average value of WW.
sample is the test result, take two significant figures. A.7 Dimensional stability
Sample size: 100×100×25mm, 3 pieces per group. Instrument: Constant temperature blast drying oven, constant temperature low temperature refrigerator, vernier caliper. X100
Steps: a. Measure the size of the sample according to the position A1 in Figure (accurate to o.1mm). b. Adjust the drying oven temperature to 65±2℃ and the refrigerator temperature to -30±2℃ respectively. (A5)
c. Place the sample flat in a drying oven and refrigerator, with the distance between the samples not less than 20 mm, and take it out after six hours of constant temperature. Place it at room temperature for 1 hour, and then measure the size of the part A1 in Figure. Calculation formula:
X is the larger number between X and X,.
In the formula: X is the rate of change of sample dimension, %, XB is the rate of change of B dimension, %,
XL is the rate of change of L dimension, %
(B.):-(Bo)i× 100
(Lt);- (Lo)ix
(L.)
(A6)
(A 7)
GB 4303--84
(B,): the B dimension of the sample with the largest change after constant temperature, mm, (L,);
the L dimension of the sample with the largest change after constant temperature, mm; (B.)—
the reference number of the B dimension of the sample with the largest change, mm (L.)i
the reference number of the L dimension of the sample with the largest change, mm. The arithmetic mean of the samples is the test result, and two significant figures are taken. Additional Notes:
This standard was proposed by China State Shipbuilding Corporation and is under the jurisdiction of Guangzhou Shipyard. This standard was drafted by Tianjin No. 15 Plastic Products Factory and Tianjin Ship Inspection Office. The main drafters of this standard are Gu Songzhen and Xi Xueshi.2 Determination of bulk density
Sample size: 50×50×25mm, 3 pieces per group. Instrument: industrial analytical balance (sensitivity 0.1g), steel ruler (reading value 0.5mm). Steps: Measure the length, width and height of the sample, accurate to 0.5mm. Measure three points each and take the arithmetic mean. Then place the sample in a desiccator (the lower desiccant is calcium chloride), take it out after 4 hours, and weigh it on the balance. Calculation formula:
W-
sample bulk density, kg/m2,
W-sample weight, g,
L-sample length, cm,
B-sample width, cmz
H-sample height, cm. The arithmetic mean of the
sample is the test result, take three significant figures. A.3 Determination of chemical stability
A.3.1 Determination of acid, alkali and salt resistance
×1000
（A1）
Take 3 samples of 50×50×25mm in each group. Tie weights to each sample and immerse it in 20% sulfuric acid aqueous solution, 45% caustic soda aqueous solution and 3% sodium chloride aqueous solution at 23±2℃. Take out the sample after 24 hours and check whether the sample has changed. A.3.2 Determination of oil resistance
Sample size: 100×100×25mm. 3 samples in each group. Instrument: Vernier caliper, oil bath device.
Steps: After measuring the size according to Figure A1, tie weights to each sample and immerse it in diesel oil at an oil temperature of 23±2℃. Take it out after 24 hours. Wipe the surface with filter paper and measure the size accurately to 0.1mm. Calculation formula:
(B); -(B。);
(B。);
(Lt)- (Lo)i × 100.
（A3）
α is the larger of α and α.
Linear expansion rate of a sample, %,
Where: α -
GB 4303-84
Linear expansion rate of a sample in B direction, %,
Linear expansion rate of a sample in L direction, %,
（Bt）—The maximum change in the B dimension of the sample after immersion, mm, (Lt): The maximum change in the L dimension of the sample after immersion, mm (Bo);
The reference number of the maximum change in the B dimension of the sample, mm, (Lo);
The reference number of the maximum change in the L dimension of the sample, mm. The arithmetic mean of the samples is the test result, rounded to two significant figures. A.4 Determination of heat resistance
A.4.1 Determination of heat resistance
Specimen size: 100×100×25mm, 3 pieces per group. Instrument: constant temperature box, steel ruler.
(Ls)
Steps: Place the specimens flat on the metal mesh in a constant temperature box at 65±2℃, with the distance between the specimens not less than 25mm. Take them out after 8 hours. Check that their appearance should not be sticky.
A.4.2 Determination of cold resistance
Specimen size: 100×100×25mm, 3 pieces per group. Instrument: low temperature refrigerator, steel ruler.
Steps: Place the specimens in a low temperature refrigerator at -30±2℃, take them out after 8 hours, and check that their appearance should not have cracks. A.5 Determination of water absorption
Specimen size: 100×100×25mm, 3 pieces per group. Instruments: analytical balance (sensitivity 0.0001g), vernier caliper. Steps: a. Measure the size of the sample to an accuracy of 1 mm. Measure three points each and calculate the arithmetic mean. b. Place the sample in a desiccator filled with calcium chloride, take it out after 24 hours and weigh it on a balance. Then immerse the sample in a glass container filled with distilled water to a depth of 50mm, the water temperature is 25±2℃, and take it out after 24 hours. Use filter paper to absorb the surface moisture 555
GB 4303-84
and weigh it. The removal, absorbing and weighing of the sample should be completed within 3 minutes. Calculation formula:
Where: Ws-
—water absorption per unit area, kg/m2,
G1—weight of the sample before immersion in water, g,
—weight of the sample after immersion in water, g,
S—total surface area of the sample, cm2
The arithmetic mean of the sample is the test result, take two significant figures. A.6 Determination of buoyancy loss after compression
Sample size: 100×100×75mm, 3 pieces per group. X 10
Instrument: pharmaceutical balance (sensitivity 1g); 120×120mm rigid flat plate-block and a weight (total weight 88±1kg). Steps: a. Measure the buoyancy of the sample according to the method in Section 5.1 of Chapter 5 (change the scale to a pharmaceutical balance). b. Place the sample flat on a smooth and hard surface. Make one 100×100mm surface of the sample face upward. Place a flat plate on the sample and press a heavy object on the plate. Take out the sample after one hour, measure its buoyancy again after the sample recovers for 5 minutes, and calculate the buoyancy loss.
Calculation formula:
W—the buoyancy of the sample after compression, g, Wsy the percentage of buoyancy loss after compression, %. The calculated average value of WW.
sample is the test result, take two significant figures. A.7 Dimensional stability
Sample size: 100×100×25mm, 3 pieces per group. Instrument: Constant temperature blast drying oven, constant temperature low temperature refrigerator, vernier caliper. X100
Steps: a. Measure the size of the sample according to the position A1 in Figure (accurate to o.1mm). b. Adjust the drying oven temperature to 65±2℃ and the refrigerator temperature to -30±2℃ respectively. (A5)
c. Place the sample flat in a drying oven and refrigerator, with the distance between the samples not less than 20 mm, and take it out after six hours of constant temperature. Place it at room temperature for 1 hour, and then measure the size of the part A1 in Figure. Calculation formula:
X is the larger number between X and X,.
In the formula: X is the rate of change of sample dimension, %, XB is the rate of change of B dimension, %,
XL is the rate of change of L dimension, %
(B.):-(Bo)i× 100
(Lt);- (Lo)ix
(L.)
(A6)
(A 7)
GB 4303--84
(B,): the B dimension of the sample with the largest change after constant temperature, mm, (L,);
the L dimension of the sample with the largest change after constant temperature, mm; (B.)—
the reference number of the B dimension of the sample with the largest change, mm (L.)i
the reference number of the L dimension of the sample with the largest change, mm. The arithmetic mean of the samples is the test result, and two significant figures are taken. Additional Notes:
This standard was proposed by China State Shipbuilding Corporation and is under the jurisdiction of Guangzhou Shipyard. This standard was drafted by Tianjin No. 15 Plastic Products Factory and Tianjin Ship Inspection Office. The main drafters of this standard are Gu Songzhen and Xi Xueshi.2 Determination of bulk density
Sample size: 50×50×25mm, 3 pieces per group. Instrument: industrial analytical balance (sensitivity 0.1g), steel ruler (reading value 0.5mm). Steps: Measure the length, width and height of the sample, accurate to 0.5mm. Measure three points each and take the arithmetic mean. Then place the sample in a desiccator (the lower desiccant is calcium chloride), take it out after 4 hours, and weigh it on the balance. Calculation formula:
W-
sample bulk density, kg/m2,
W-sample weight, g,
L-sample length, cm,
B-sample width, cmz
H-sample height, cm. The arithmetic mean of the
sample is the test result, take three significant figures. A.3 Determination of chemical stability
A.3.1 Determination of acid, alkali and salt resistance
×1000
（A1）
Take 3 samples of 50×50×25mm in each group. Tie weights to each sample and immerse it in 20% sulfuric acid aqueous solution, 45% caustic soda aqueous solution and 3% sodium chloride aqueous solution at 23±2℃. Take out the sample after 24 hours and check whether the sample has changed. A.3.2 Determination of oil resistance
Sample size: 100×100×25mm. 3 samples in each group. Instrument: Vernier caliper, oil bath device.
Steps: After measuring the size according to Figure A1, tie weights to each sample and immerse it in diesel oil at an oil temperature of 23±2℃. Take it out after 24 hours. Wipe the surface with filter paper and measure the size accurately to 0.1mm. Calculation formula:
(B); -(B。);
(B。);
(Lt)- (Lo)i × 100.
（A3）
α is the larger of α and α.
Linear expansion rate of a sample, %,
Where: α -
GB 4303-84
Linear expansion rate of a sample in B direction, %,
Linear expansion rate of a sample in L direction, %,
（Bt）—The maximum change in the B dimension of the sample after immersion, mm, (Lt): The maximum change in the L dimension of the sample after immersion, mm (Bo);
The reference number of the maximum change in the B dimension of the sample, mm, (Lo);
The reference number of the maximum change in the L dimension of the sample, mm. The arithmetic mean of the samples is the test result, rounded to two significant figures. A.4 Determination of heat resistance
A.4.1 Determination of heat resistance
Specimen size: 100×100×25mm, 3 pieces per group. Instrument: constant temperature box, steel ruler.
(Ls)
Steps: Place the specimens flat on the metal mesh in a constant temperature box at 65±2℃, with the distance between the specimens not less than 25mm. Take them out after 8 hours. Check that their appearance should not be sticky.
A.4.2 Determination of cold resistance
Specimen size: 100×100×25mm, 3 pieces per group. Instrument: low temperature refrigerator, steel ruler.
Steps: Place the specimens in a low temperature refrigerator at -30±2℃, take them out after 8 hours, and check that their appearance should not have cracks. A.5 Determination of water absorption
Specimen size: 100×100×25mm, 3 pieces per group. Instruments: analytical balance (sensitivity 0.0001g), vernier caliper. Steps: a. Measure the sample size to an accuracy of 1 mm. Measure three points each and calculate the arithmetic mean. b. Place the sample in a desiccator filled with calcium chloride, take it out after 24 hours and weigh it on a balance. Then immerse the sample in a glass container filled with distilled water to a depth of 50mm, the water temperature is 25±2℃, and take it out after 24 hours. Use filter paper to absorb the surface moisture 555
GB 4303-84
and weigh it. The removal, absorbing and weighing of the sample should be completed within 3 minutes. Calculation formula:
Where: Ws-
—water absorption per unit area, kg/m2,
G1—weight of the sample before immersion in water, g,
—weight of the sample after immersion in water, g,
S—total surface area of the sample, cm2
The arithmetic mean of the sample is the test result, take two significant figures. A.6 Determination of buoyancy loss after compression
Sample size: 100×100×75mm, 3 pieces per group. X 10
Instrument: pharmaceutical balance (sensitivity 1g); 120×120mm rigid flat plate-block and a weight (total weight 88±1kg). Steps: a. Measure the buoyancy of the sample according to the method in Section 5.1 of Chapter 5 (change the scale to a pharmaceutical balance). b. Place the sample flat on a smooth and hard surface. Make one 100×100mm surface of the sample face upward. Place a flat plate on the sample and press a heavy object on the plate. Take out the sample after one hour, measure its buoyancy again after the sample recovers for 5 minutes, and calculate the buoyancy loss.
Calculation formula:
W—the buoyancy of the sample after compression, g, Wsy the percentage of compression buoyancy loss, %. The calculated average value of WW.
sample is the test result, take two significant figures. A.7 Dimensional stability
Sample size: 100×100×25mm, 3 pieces per group. Instrument: Constant temperature blast drying oven, constant temperature low temperature refrigerator, vernier caliper. X100
Steps: a. Measure the size of the sample according to the position A1 in Figure (accurate to o.1mm). b. Adjust the drying oven temperature to 65±2℃ and the refrigerator temperature to -30±2℃ respectively. (A5)
c. Place the sample flat in a drying oven and refrigerator, with the distance between the samples not less than 20 mm, and take it out after six hours of constant temperature. Place it at room temperature for 1 hour, and then measure the size of the part A1 in Figure. Calculation formula:
X is the larger number between X and X,.
In the formula: X is the rate of change of sample dimension, %, XB is the rate of change of B dimension, %,
XL is the rate of change of L dimension, %
(B.):-(Bo)i× 100
(Lt);- (Lo)ix
(L.)
(A6)
(A 7)
GB 4303--84
(B,): the B dimension of the sample with the largest change after constant temperature, mm, (L,);
the L dimension of the sample with the largest change after constant temperature, mm; (B.)—
the reference number of the B dimension of the sample with the largest change, mm (L.)i
the reference number of the L dimension of the sample with the largest change, mm. The arithmetic mean of the samples is the test result, and two significant figures are taken. Additional Notes:
This standard was proposed by China State Shipbuilding Corporation and is under the jurisdiction of Guangzhou Shipyard. This standard was drafted by Tianjin No. 15 Plastic Products Factory and Tianjin Ship Inspection Office. The main drafters of this standard are Gu Songzhen and Xi Xueshi.
（A3）
α is the larger of α and α.
Linear expansion rate of a sample, %,||t
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