Analysis of European airtight, watertight, and wind pressure resistance test standards for exterior doors and windows.

1. Research background

Products entering the EU market must have the CE mark. For some products that fall within the scope of mandatory supervision, approval by the EU Notified Body is required. Although the UK has entered the state of leaving the EU, the access requirements and standards for most products are not independent of each other. It is just the market access method that has changed. Building exterior doors and windows are among such products that need to be recognized. According to the standard requirements of "EN14351-1 Standard Performance Characteristics of Door and Window Products-1 Building Exterior Windows and Doors", exterior door and window products are level 3 products subject to mandatory supervision and must be tested and passed by an EU-notified body before the manufacturer can The corresponding CE label is used on the product. The EN14351-1 standard stipulates a series of performance requirements that exterior doors and windows of buildings need to meet, including but not limited to wind resistance, snow load resistance, fire response, fire resistance, water tightness, impact resistance, safety device carrying capacity, acoustic performance, Thermal performance, radiation, air tightness, opening force, mechanical strength, ventilator, repeated opening and closing performance, etc. Among them, air tightness, water tightness, and wind pressure resistance are the basic performance requirements for exterior doors and windows. This article will analyze and interpret the corresponding standards from the perspective of three performance (hereinafter referred to as three properties) tests.

The composition of the European tertiary testing standards is different from that of the United States, Australia, and China. The American standard is a test method standard for each test, and a general product standard includes test classification. Australian standards are a general testing method standard and a general product standard including test classification. Chinese country's GB/T7106-2008 "Classification and Testing of Airtightness, watertightness, and Wind Pressure Resistance of Building Exterior Doors and Windows" is a general test method standard and multiple product standards. The old version of the grading index was in the test method standard, but the new version of GB/T7106-2019 "Testing Method for Airtightness, Watertightness, and Wind Pressure Resistance of Building Exterior Doors and Windows" has canceled the grading and is graded by each product standard. Relatively speaking, among the old grading indicators, the overall requirements of the national standard are relatively low, and there is a certain gap with foreign standards. As the quality of domestic products gradually improves, they should gradually integrate with foreign standards. The European standard adopts that each test corresponds to a test method standard, a classification and judgment standard, and then is summarized by a general product standard. The function of each standard is clear, but the number of standards to be checked in actual operation is indeed quite large. The corresponding standards for the European standard three-property test are shown in Table 1.

Table 1 European three-performance test corresponding standards

2. The testing requirements

In the European standard, since the three tests are expressed in different standards, there is no prescribed order of tests. However, the wind pressure resistance test includes repeated air tightness, and the moisture of the sample after the water tightness test will affect the air tightness results, so the usual test order is air tightness, water tightness, and wind pressure resistance (including repeated air tightness test). Generally, the three tests are completed on one set of testing equipment for samples with different installation angles. For example, the water tightness test of a skylight may require two sets of samples.

The basic composition of door and window three-property testing equipment is as follows

1 fan; 2 pressure control system; 3 flow meter; 4 water flow meter; 5 differential pressure meter; 6 test box; 7 displacement test component; 8 spray device, etc. Depending on the installation orientation of the sample, the equipment has internal spray and There are two forms of external spray. The European standard mainly uses internal spraying for experimental design, but external spraying can also be used for testing.

2.1 Air tightness test

The European standard air tightness test first needs to determine the gas leakage of the box (test system). If the leakage of the box is less than 5% of the grade limit of the test sample, the leakage of the box can be ignored. However, it is difficult to predict sample leakage before testing, so conventional testing methods are generally used, that is, testing the additional leakage of the box once and testing the total leakage (including box and sample leakage). The leakage of the box should be controlled within 30% of the total leakage. The air tightness test process is as follows.

(1) When the leakage of the box is ignored, as shown in Figure 1. First, switch the sample on and off, check the function of the sample, add positive pressure for three pulses of 660Pa, and then conduct a formal positive pressure test. The pressure sequence is 50, 100, 150, 200, 250, 300, 450, 600Pa. The negative pressure test sequence is the same as that of positive pressure +Pa-Pa

Figure 1 Air tightness test process without considering box leakage

(2) When considering the leakage of the box, the test process is shown in Figure 2

First test the additional leakage of the box, switch the sample on and off, and check the function of the sample. Test the box and add positive pressure to the box for three pulses of 660Pa, and then conduct the formal positive pressure test. The pressure sequence is 50, 100, 150, 200, 250, 300, 450 Negative pressure test suction is the same as re-pressure 600Pa.
+Pa
-Pa

Figure 2 Air tightness test process considering box leakage

Regarding the additional leakage test, the label in the EN1026 standard is test negative pressure. This is considered based on the internal spray test device because the purpose of the additional leakage test is to test the leakage of the box. The sealed sample is on the outside. If it is sprayed internally, the outdoor side of the sample faces the box. At this time, the negative pressure is sucked into the box, so the additional leakage test uses negative pressure; if it is sprayed externally, the outdoor side of the sample faces the box. In addition, at this time, the positive pressure is sucked into the box, so the additional leakage test using positive pressure is the correct test method.

The evaluation of the European standard air tightness test is divided into two indicators: unit seam length and unit area, as shown in Table 2 and Table 3. When using the EN12207 standard, please note that this standard evaluates both exterior windows and interior windows, so pay attention to the distinction. The former needs to evaluate the air-tightness performance at a maximum pressure of 600Pa, while the latter only needs to evaluate a maximum pressure of 150Pa.

Table 2 Air leakage rate per unit area

Level air permeability per unit area (at 100Pa)/m (hm2) Maximum test pressure/Pa
150
150
227
300
39600
43600

Table 3 Air leakage rate per unit seam length
level
Air permeability per unit seam length (at 100 Pa)/m (hm)
Maximum test pressure/Pa
12.50
150
26.75
300
32.25
600
0.75
600

The air tightness test of exterior windows is divided into 4 levels, from Level 1 to Level 4. Among them, level 4 is the most stringent, and level 1 is the minimum requirement. Meeting a certain level not only means that the air permeability meets the requirements at 100Pa but also must be based on the standard calculation formula to ensure that every test pressure that does not exceed the maximum test pressure meets the requirements of the level. For example, level 4 needs to meet the requirements at 50, 100, 150, 200, 250, 300, 450, and 600Pa. The calculation formula for the flow requirements at other levels is as shown in Equation (1).
2/3
Q=Q1oo(p/100Pa)
(1)

In the formula: Q is the air permeability (limit value) under the test pressure, m/h; Q1o0 is the air leakage rate under the standard pressure of 100Pa, m/h; p is the test pressure, Pa.
There will be a test level for unit area and unit seam length respectively, but the air tightness level only has one value, so it still needs to be judged. When the two grades are the same, the air tightness grade is also the same. When two levels are adjacent (for example, one is level 2 and the other is level 3), the air tightness level shall be the better level (level 3 and a half is counted as one level). When the two levels differ by one level (such as one is level 1 and the other is level 3), the air tightness level shall be The tightness level is the middle value (level 2). When the difference between the two levels is more than one level (it can only be one level 1 and one level 4), no rating will be given.

Compared with other standard evaluation methods, the European standard air tightness rating is slightly more complicated. For non-combined exterior windows, the first two situations are more common. When the levels are adjacent, choosing a good level encourages exterior windows to open with as few gaps as possible. However, it should be noted that the latter two situations generally occur in combined exterior windows, part of which is a fixed fan and part is an open fan, resulting in a larger sample area and smaller seam length. Although the sealing performance of the open part is poor, the leakage rate per unit area can still achieve good results because of the large overall area. To prevent such products with inferior performance from entering engineering applications, it is required that no rating will be given if the difference between the leakage rate per unit area and unit seam length is large.

For products with separate fixed fans, the European standard allows no testing and is given a level 3 rating. Therefore, fixed fan products can choose to test the air tightness or directly obtain a level 3 rating (the grades of indoor windows are divided into levels A and B). Grade, C grade, D grade) Compared with the European standard, the American standard does not rate the combined exterior windows as a whole but uses a method of rating each opening type of exterior window separately. This is more beneficial for users to grasp the actual performance of the product. China's national standard GB/T71062019 no longer rates air-tightness performance. The old version took into account the craftsmanship level of domestic doors and windows and formulated looser standards. However, the craftsmanship level of doors and windows currently on the market can fully adopt higher standard requirements and benchmark European and American standards.

2.2 Water tightness test

The European standard water tightness test method uses a test method of continuous spraying and gradual pressurization. The test spray uses a row of spray pipes on the top of the sample, with a fixed spray volume and spray angle. The spray angle setting will change for products with an upper edge. Specific requirements are as follows. The spray angle of the sprinkler head can cover 120°, the water spray volume of the first row is 2L/min, and the water spray volume of the additional sprinkler head is 1L/min. The height of the sprinkler head should not exceed 150mm above the opening slit at the top of the sample and 250mm away from the surface of the sample. The spacing between sprinkler heads should be 400mm. When the height of the sample exceeds 2.5m, an additional row of sprinkler heads should be installed. From 4 hours before the test to during the test, the sample should be in an environment with a temperature of 10℃~30℃ and a humidity of 25%~75%.

The order of testing is step-by-step pressure. First, no pressure is applied for 15 minutes, and then the pressure is tested for 5 minutes every 50Pa until leakage occurs. European standard water tightness testing starts from level 0. Level 0 has no water tightness requirements, level 1 means no leakage after 15 minutes of spraying without pressure, and levels 2 to 9 correspond to the pressures of 50, 100, 150, 200, 250, 300, 450, and 600Pa in Figure 3 respectively. When the watertight performance of the sample is better than level 9, the pressure can be continued, with a pressure increase level every 150Pa, and the final pressure passed is directly marked as Ex. The water tightness test is shown in Figure 3.

600
450
300
250
200
150
100
50
15202530354045055
a t/min

Figure 3 Water tightness test process

2.3 Wind pressure resistance test

The European standard wind pressure resistance test includes four test stages, namely wind pressure deformation resistance, repeated pressurization, repeated air tightness after wind pressure, and ultimate wind pressure test. The details are shown in Table 4.

Table 4 Wind pressure resistance level/Pa

2.3.1 Wind pressure deformation test

The wind pressure deformation pressure is P1 pressure. During the test, the pressure needs to be slowly raised (100Pa/s) to the specified pressure and maintained for 30s to record the deformation of the stressed rod. Then release the pressure to 0Pa, keep it for 60, and record the residual deformation of the stressed member. Deflections are calculated separately.

2.3.2 Repeated pressure test against wind pressure

The test pressure for repeated wind pressure resistance is p2 pressure, p2=0.5p1. Repeated pressurization is under ±p pressure, with a reciprocating cycle. A complete positive and negative pressure cycle is one cycle. Test for 50 cycles and observe whether the sample has damage. The pressure at p/-p2 in each cycle should be maintained for 7±3s, and the process from p2~-P2 should also be maintained for 7±3s (i.e., the period for each pressure change)

2.3.3 Repeat air tightness test

The procedure for this test is the same as for the air tightness test. Since an additional air tightness test has been carried out, this item can no longer be performed here (this item needs to be retested when the condition of the test box changes). The repeated air tightness test is performed after the wind pressure deformation resistance and repeated air tightness tests. , it is possible that the result will be less airtight than the first time. It is required here that the repeated air tightness results cannot exceed the required value of the level of the first air tightness result multiplied by 120%, otherwise, the judgment will not pass.

2.3.4 Ultimate wind pressure test

The ultimate wind pressure test pressure is p3 pressure, p3=1.5p1. After the ultimate wind pressure test is completed, it is necessary to check whether the sample is intact, whether it can be opened and closed normally, and record whether there is any damage, falling off, etc.

3. The conclusion

Among the performance requirements of the European standard three-property test, the minimum requirements for air tightness and water tightness are lower than those of the Australian and American standards, but actual project requirements are specified by the owner. Under the relatively high building energy conservation regulations in Europe, most actual project performance requirements require higher levels, even exceeding the most advanced requirements. At the same time, there are also certain requirements for the heat transfer coefficient and acoustic performance of the product. Skylight products also place requirements on hardware performance. European standard EN14351-1 is the main standard for performance requirements for exterior doors and windows in buildings. It stipulates in detail the performance requirements that door and window products must meet. The three properties of exterior doors and windows are the basic performance requirements for doors and windows. This article details these testing methods and basic requirements, which can be used as a reference for technicians who implement testing, door and window suppliers, and managers of engineering projects in Europe.