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Influence of internal pressure equalization on static quantities in climatically loaded insulating glass units Cover

Influence of internal pressure equalization on static quantities in climatically loaded insulating glass units

Architecture, Civil Engineering, Environment

Volume 19 (2026): Issue 1 (March 2026)

By: Zbigniew Respondek

Open Access

|Sep 2026

Figures & tables

Figures & Tables

“Pillowing” of IGU component panes causing distortion of the reflected image.

Subscripts used to designate component panes and cavities; location of low-e films (dashed line): (a) 3-glazed IGU and (b) 4-glazed IGU.

Table 1

Temperature distribution in IGUs at wind speed of 4 m/s

Parameter	Vertical IGU, t _e = −10°C			Horizontal IGU, cloudy sky, t _e = −10°C			Horizontal IGU, clear sky, t _e = −10°C, t _r = −32.34°C
Parameter	2-glazed	3-glazed	4-glazed	2-glazed	3-glazed	4-glazed	2-glazed	3-glazed	4-glazed
ϑ _ex (°C)	−8.44	−9.12	−9.40	−7.56	−8.73	−9.18	−10.17	−11.47	−11.97
t _m1 (°C)	3.39	−2.30	−4.61	3.35	−2.29	−4.63	1.71	−4.44	−7.00
t _m2 (°C)	−	10.88	4.73	−	10.52	4.40	−	9.56	2.88
t _m3 (°C)	−	−	13.72	−	−	13.48	−	−	12.81
ϑ _in (°C)	15.22	17.34	18.16	14.26	17.01	18.06	13.61	16.66	17.83
U (W/m²K)	1.225	0.683	0.472	1.914	0.997	0.645	2.132	1.113	0.722

Source: Author’s contribution.

Table 2

Temperature distribution in IGUs, in windless weather

Parameter	Vertical IGU, t _e = −10°C			Horizontal IGU, cloudy sky, t _e = −10°C			Horizontal IGU, clear sky, t _e = −10°C, t _r = −32.34°C
Parameter	2-glazed	3-glazed	4-glazed	2-glazed	3-glazed	4-glazed	2-glazed	3-glazed	4-glazed
ϑ _ex (°C)	−5.60	−7.43	−8.19	−3.68	−6.42	−7.59	−10.43	−14.20	−15.85
t _m1 (°C)	5.04	−1.01	−3.60	5.76	−0.49	−3.29	1.55	−6.57	−10.92
t _m2 (°C)	−	11.42	5.36	−	11.23	5.26	−	8.60	0.77
t _m3 (°C)	−	−	13.98	−	−	13.85	−	−	11.88
ϑ _in (°C)	15.69	17.49	18.23	15.21	17.30	18.19	13.54	16.30	17.50
U (W/m²K)	1.105	0.644	0.453	1.597	0.899	0.603	2.154	1.232	0.832

Source: Author’s contribution.

Temperature distribution in a quadruple-glazed IGU located horizontally (no wind).

Table 3

Static quantities in SYM IGUs (4-12-4-12-4 or 4-12-4-12-4-12-4)

IGU type, location	Glass pane	Sealed cavities			Internally unsealed cavities
IGU type, location	Glass pane	q (kN/m²)	w (mm)	σ _x (MPa)	q (kN/m²)	w (mm)	σ _x (MPa)
3-glazed IGU, vertically	ex	0.467	1.58	6.30	0.407	1.37	5.49
	1-2	−0.120	−0.40	1.62	—	—	—
	in	−0.347	−1.17	4.68	−0.407	−1.37	5.49
4-glazed IGU, vertically	ex	0.694	2.34	9.37	0.576	1.95	7.78
	1-2	0.060	0.20	0.81	—	—	—
	2-3	−0.307	−1.04	4.15	—	—	—
	in	−0.447	−1.51	6.03	−0.576	−1.95	7.78
3-glazed IGU, horizontally	ex	0.661	2.23	8.93	0.592	2.00	7.99
	1-2	−0.038	−0.13	0.51	0.100	0.34	1.35
	in	−0.323	−1.09	4.36	−0.392	−1.32	5.29
4-glazed IGU, horizontally	ex	0.975	3.29	13.17	0.828	2.80	11.18
	1-2	0.178	0.60	2.40	0.100	0.34	1.35
	2-3	−0.286	−0.96	3.86	0.100	0.34	1.35
	in	−0.467	−1.58	6.31	−0.628	−2.12	8.48

Source: Author’s contribution.

Table 4

Static quantities in SYM IGUs for critical widths

IGU type, location	Sealed cavities				Internally unsealed cavities				Diff
IGU type, location	a _cr (cm)	q (kPa)	w (mm)	σ _x (MPa)	a _cr (cm)	q (kPa)	w (mm)	σ _x (MPa)	Diff
3-glazed IGU, vertically	30.8	3.602	0.84	12.82	32.1	2.716	0.75	10.49	−18,2%
4-glazed IGU, vertically	33.9	3.702	1.27	15.96	35.5	2.660	1.10	12.58	−21,2%
3-glazed IGU, horizontally	31.1	4.344	1.06	15.76	32.6	3.292	0.97	13.10	−16,9%
4-glazed IGU, horizontally	33.7	4.838	1.63	20.60	36.0	3.369	1.48	16.41	−20,4%

Source: Author’s contribution.

Table 5

Static quantities LAM IGUs (4-12-4-12-44.2 or 4-12-4-12-4-12-44.2)

IGU type, location	Glass pane	Sealed cavities			Internally unsealed cavities
IGU type, location	Glass pane	q (kN/m²)	w (mm)	σ _x (MPa)	q (kN/m²)	w (mm)	σ _x (MPa)
3-glazed IGU, vertically	ex	0.626	2.11	8.46	0.637	2.15	8.60
	1-2	0.052	0.17	0.70	—	—	—
	in	−0.678	−0.50	2.73	−0.637	−0.47	2.57
4-glazed IGU, vertically	ex	0.850	2.87	11.48	0.886	2.99	11.96
	1-2	0.228	0.77	3.08	—	—	—
	2-3	−0.114	−0.38	1.54	—	—	—
	in	−0.964	−0.71	3.89	−0.886	−0.66	3.57
3-glazed IGU, horizontally	ex	0.823	2.78	11.11	0.830	2.80	11.20
	1-2	0.136	0.46	1.83	0.100	0.34	1.35
	in	−0.558	−0.41	2.25	−0.530	−0.39	2.14
4-glazed IGU, horizontally	ex	1.149	3.88	15.51	1.181	3.99	15.95
	1-2	0.364	1.23	4.91	0.100	0.34	1.35
	2-3	−0.071	−0.24	0.96	0.100	0.34	1.35
	in	-0.942	-0.70	−3.80	−0.881	−0.65	3.55

Source: Author’s contribution.

Table 6

Static quantities in LAM IGUs for critical widths

IGU type, location	Sealed cavities				Internally unsealed cavities				Diff
IGU type, location	a _cr (cm)	q (kPa)	w (mm)	σ _x (MPa)	a _cr (cm)	q (kPa)	w (mm)	σ _x (MPa)	Diff
3-glazed IGU, vertically	34.1	3.203	1.13	13.97	36.3	2.716	1.23	13.43	−3,9%
4-glazed IGU, vertically	36.1	3.388	1.5	16.56	40.2	2.660	1.81	16.11	−2,7%
3-glazed IGU, horizontally	33.9	3.994	1.37	17.21	36.6	3.316	1.55	16.65	−3,3%
4-glazed IGU, horizontally	36.5	4.289	1.98	21.43	40.1	3.394	2.38	20.87	−2,6%

Source: Author’s contribution.

Table 7

Static quantities in RLAM IGUs for critical widths

IGU type, location	Sealed cavities				Internally unsealed cavities				Diff
IGU type, location	a _cr (cm)	q (kPa)	w (mm)	σ _x (MPa)	a _cr (cm)	q (kPa)	w (mm)	σ _x (MPa)	Diff
3-glazed IGU, vertically	38.8	−1.928	−1.14	10.88	36.3	−2.716	−1.23	13.43	23,4%
4-glazed IGU, vertically	44.7	−1.475	−1.53	11.05	40.2	−2.660	−1.81	16.11	45,8%
3-glazed IGU, horizontally	38.1	−2.353	−1.29	12.81	36.0	−3.265	−1.43	15.89	24,1%
4-glazed IGU, horizontally	44.5	−1.805	−1.84	13.40	39.9	−3.343	−2.20	19.93	48,7%

Source: Author’s contribution.

Articles in this issue

DOI: https://doi.org/10.2478/acee-2026-0008 | Journal eISSN: 2720-6947 (formerly 1899-0142) | Journal ISSN: 1899-0142

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Language: English

Page range: 84 - 94

Submitted on: Jul 8, 2025

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Accepted on: Dec 9, 2025

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Published on: Sep 3, 2026

Published by: Silesian University of Technology

In partnership with: Paradigm Publishing Services

Publication frequency: Volume open

Keywords:

Climatic loads,

Deflection of glass panes,

Insulating glass units,

Radiative cooling,

Stress in glass

Related subjects:

Architecture and design,

Architects, buildings

© 2026 Zbigniew Respondek, published by Silesian University of Technology
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Volume 19 (2026): Issue 1 (March 2026)

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