An indoor environmental quality assessment of office spaces at an urban Australian university

Figures & data

Figure 1. IEQ measurement instrumentation.

Table 1. Instrument description.

Type of instrument	Parameter	Measuring range and accuracy
Testo 480 Testo 816	Air temperature (°C) Relative humidity (%) CO2 concentration (ppm) Globe temperature (°C) Air velocity (ms^−1) Lux meter Sound level meter	0 to +50°C, ±0.5°C 0 to 100RH%, ±(1.8RH% + 0.7% or measured value) 0 to +10000, ±(75 ppm CO2 + 3% of measured value) 0 to +120°C, Class 1 0 to +5ms^−1, ±(0.03ms^−1 to 4% of measured value) 0–100,000 lux (1) 30–130 dBA; ±1.4 dB (under reference conditions  94 dB, 1 kHz)

Figure 2. Facades of three building types. Image source: RMIT University.

Table 2. Building characteristics.

Building type	Name of Building	Year of Built	Total floors	GFA (m^2)	Office level	Workspace area (m^2)	Occupant density (m^2/person)	Ceiling height (m)	Building depth (m)	Office function
Type 1	A	1891	3	3350	A03	87	6	4.3	5	Admin.
Type 1	B	1860	3	1761	B02	624	5	3	3	Admin.
Type 2	C	1960	7	1747	C03	348	6	2.7	8	Admin.
Type 2	D	1969	18	33,660	D04 & D12	1389	6	3	10	Admin.
Type 2	E	1978	14	28,790	E09 & E10	1127	6	2.8	17	Legal, Property services
Type 2	F	1984	10	11,251	F05, F06, F07, F08, F09 & F10	1632	8	2.7	28	Academic registrar’s group, Information technology services
Type 3	G	2005	27	58,530	G27	1706	7	2.7	18	Property services

Note: Office level indicates the floors investigated in the selected building.

Table 3. Building envelope and HVAC system details.

Building name	HVAC system	HVAC distribution	Construction	Glazing type	Window to wall ratio
A	Centralized CAV, radiant wall-mounted heaters	Ceiling mounted diffusers	Masonry block, slate roof	Double	10%
B	Centralized CAV, radiant wall-mounted heaters	Ceiling mounted diffusers	Masonry block, slate roof	Single	10%
C	Centralized CAV	Ceiling mounted diffusers	Brick, concrete slab	Single	45%
D	Centralized CAV	Ceiling mounted diffusers	Concrete column and slab, precast panel	Single	70%
E	Centralized CAV	Ceiling mounted diffusers	Concrete column and slab, precast panel	Single	78%
F	Centralized VAV, modulating outside air flowrate	Ceiling mounted diffusers	Concrete column and slab, precast panel	Single	66%
G	Centralized CAV with perimeter reheat	Ceiling mounted diffusers	Concrete column and slab, precast panel	Double-glazing, tint	88%

Figure 3. Temperature and RH (a) and (b) CO₂ concentration measured inside the offices.

Figure 4. Lighting levels (a) and sound levels (b).

Note. No sound levels were measured in the buildings A and B.

Table 4. PMV, PPD and thermal comfort compliance (met: 1.2, clo:0.61).

Office	Temp (°C)	RH (%)	Air velocity (m/s)	Globe temp (°C)	MRT (°C)	Operative temp (°C)	PMV	PPD (%)	Compliance with ASHRAE Standard 55-2020
A03	22.75	38.46	0.05	22.84	22.87	22.80	−0.40	8	Y
B02	23.64	35.75	0.08	23.68	23.70	23.66	−0.20	6	Y
D04	22.57	32.98	0.09	29.50	33.08	26.04	0.38	8	Y
D12	21.64	33.72	0.07	21.81	21.89	21.73	−0.72	16	N
E09	22.65	31.25	0.06	22.75	22.79	22.70	−0.47	10	Y
E10	22.57	31.26	0.14	22.67	22.74	22.62	−0.70	15	N
F05	22.85	36.26	0.07	22.87	22.88	22.86	−0.40	8	Y
F06	22.23	35.97	0.06	22.16	22.14	22.20	−0.58	12	N
F08	23.04	33.95	0.05	23.02	23.00	23.03	−0.37	8	Y
F09	22.59	34.89	0.05	22.00	21.77	22.30	−0.56	12	N
F10	23.10	34.66	0.06	22.98	22.93	23.04	−0.36	8	Y
G27	23.12	32.98	0.08	23.18	23.21	23.15	−0.34	7	Y

Figure 5. Occupant perception of indoor condition parameters.

Figure 6. Overall comfort and satisfaction and perceived productivity.

Table 5. Correlations between subjective and objective assessments.

Subjective criteria	Objective criteria	r	p	r^2
Thermal sensation (too cold – too hot)	Air temperature	0.198**	0.000	0.039
	CO2 concentration	0.265**	0.000	0.070
Temperature stability (stable – varies)	Air velocity	0.122**	0.008	0.015
Air movement (still – draughty)	Air velocity	0.019	0.684	0.000
Humidity (dry – humid)	RH	0.028	0.542	0.001
Air freshness (fresh – stale)	CO2 concentration	0.037	0.418	0.001
Odour (odourless – smelly)	RH	0.121**	0.008	0.015
	CO2 concentration	0.042	0.365	0.002
Noise overall (very quiet – very noisy)	Sound level	0.127**	0.006	0.016
Lighting overall (Very dark – very bright)	Lighting level	0.046	0.312	0.002

**Correlation is significant at the 0.01 level (2-tailed).

Table 6. Welch’s F test for indoor environment by three building types.

	F	df1	df2	sig.	est.ω^2
Thermal sensation	7.160	2	77.826	0.001	0.02
Temperature stability	2.496	2	65.043	0.090	0.01
Air movement	4.752	2	66.879	0.012	0.02
Humidity	2.045	2	71.373	0.137	0.00
Air freshness	3.574	2	68.539	0.033	0.01
Odour	6.985	2	69.041	0.002	0.02
Noise overall	4.925	2	66.168	0.010	0.02
Noise from colleagues conversations	0.402	2	65.147	0.670	0.00
Noise from phone ringing/text messaging/notifications/etc	0.132	2	68.018	0.876	0.00
Noise from inside the building	4.744	2	68.174	0.012	0.01
Noise from outside the building	6.633	2	69.566	0.002	0.02
Lighting overall	0.119	2	69.226	0.888	0.00
Lighting from natural light	9.935	2	70.943	0.000	0.03
Lighting from artificial light	0.687	2	70.288	0.506	0.00
Glare from sun and sky	2.853	2	66.303	0.065	0.01
Glare from lights	0.898	2	63.322	0.413	0.00

Table 7. Post hoc results for indoor environment by three building types.

	Building type	Mean (M)	Mean differences (Md)
			1	2	3
Thermal sensation	1	4.10	–	−0.517*	−0.097
	2	3.58	0.517*	–	0.421*
	3	4.00	0.097	−0.421*	–
	Total	3.67
Air movement	1	3.37	–	0.318	−0.205
	2	3.68	−0.318	–	−0.523*
	3	3.16	0.205	0.523*	–
	Total	3.60
Air freshness	1	4.42	–	0.109	−0.337
	2	4.53	−0.109	–	−0.446*
	3	4.08	0.337	0.446*	–
	Total	4.47
Odour	1	3.61	–	0.167	−0.565
	2	3.78	−0.167	–	−0.732*
	3	3.05	0.565	0.732*	–
	Total	3.67
Noise overall	1	4.25	–	0.518	0.104
	2	4.77	−0.518	–	−0.414*
	3	4.35	−0.104	0.414*	–
	Total	4.68
Noise from inside the building	1	3.53	–	0.544	0.053
	2	4.08	−0.544	–	−0.491
	3	3.58	−0.053	0.491	–
	Total	3.98
Noise from outside the building	1	4.09	–	−0.647	−1.232*
	2	3.45	0.647	–	−0.586*
	3	2.86	1.232*	0.586*	–
	Total	3.41
Lighting from natural light	1	3.38	–	−0.325	0.471
	2	3.05	0.325	–	0.796*
	3	3.85	−0.471	−0.796*	–
	Total	3.17

*The mean difference is significant at the 0.05 level.

Table 8. Welch’s F test for spatial comfort and amenities by three building types.

	F	df1	df2	sig.	est.ω^2
Spatial comfort overall	15.968	2	73.414	0.000	0.06
Individual workspace	0.360	2	73.612	0.699	0.00
Team space	0.194	2	71.684	0.824	0.00
Personal storage	5.358	2	70.664	0.007	0.02
Shared storage	0.994	2	66.985	0.375	0.00
Visual privacy	1.313	2	70.727	0.275	0.00
Desk	1.323	2	68.538	0.273	0.00
Chair	4.845	2	67.560	0.011	0.02
General décor	16.694	2	70.111	0.000	0.06
Plants/greenery	6.448	2	65.675	0.003	0.02
Amenities overall	46.601	2	72.125	0.000	0.15
Views to outside	49.754	2	67.047	0.000	0.16
Internal signage	15.120	2	61.185	0.000	0.05
Office equipment	1.730	2	64.950	0.185	0.00
Refreshment facilities	22.174	2	66.275	0.000	0.08
Security	26.008	2	69.051	0.000	0.09
Safety provision	22.190	2	67.340	0.000	0.08
General tidiness	13.995	2	66.027	0.000	0.05
General cleanliness	17.597	2	67.584	0.000	0.06

Table 9. Post hoc results for spatial comfort and amenities by three building types.

	Building type	Mean (M)	Mean differences (Md)
			1	2	3
Spatial comfort overall	1	4.53	–	−0.428	0.408
	2	4.10	0.428	–	0.836*
	3	4.94	−0.408	−0.836*	–
	Total	4.24
Personal storage	1	3.87	–	−0.536	−0.083
	2	3.34	0.536	–	0.453*
	3	3.79	0.083	−0.453*	–
	Total	3.43
Chair	1	4.75	–	−0.509	0.050
	2	4.24	0.509	–	0.559*
	3	4.80	−0.050	−0.559*	–
	Total	4.35
General décor	1	4.56	–	−1.193*	−0.409
	2	3.37	1.193*	–	0.785*
	3	4.15	0.409	−0.785*	–
	Total	3.55
Plants/greenery	1	3.66	–	−0.624	0.082
	2	3.03	0.624	–	0.706*
	3	3.74	−0.082	−0.706*	–
	Total	3.16
Amenities overall	1	4.72	–	−1.110*	0.281
	2	3.61	1.110*	–	1.392*
	3	5.00	−0.281	−1.392*	–
	Total	3.86
Views to outside	1	4.60	–	−1.059*	1.057*
	2	3.54	1.059*	–	2.116*
	3	5.66	−1.057*	−2.116*	–
	Total	3.89
Internal signage	1	4.38	–	−0.530	0.378
	2	3.85	0.530	–	0.908*
	3	4.76	−0.378	−0.908*	–
	Total	4.00
Refreshment facilities	1	4.06	–	−0.065	1.085*
	2	4.00	0.065	–	1.149*
	3	5.15	−1.085*	−1.149*	–
	Total	4.16
Security	1	4.84	–	−0.498	0.631
	2	4.34	0.498	–	1.129*
	3	5.47	−0.631	−1.129*	–
	Total	4.52
Safety provision	1	4.61	–	−0.260	0.842*
	2	4.35	0.260	–	1.101*
	3	5.45	−0.842*	−1.101*	–
	Total	4.51
General tidiness	1	4.68	–	−0.466	0.429
	2	4.21	0.466	–	0.895*
	3	5.11	−0.429	−0.895*	–
	Total	4.36
General cleanliness	1	4.81	–	−0.730*	0.300
	2	4.08	0.730*	–	1.030*
	3	5.11	−0.300	−1.030*	–
	Total	4.26

Table 10. Welch’s F test for overall comfort and satisfaction in the workplace.

	F	df1	df2	sig.	est. ω^2
Overall comfort	16.407	2	74.123	0.000	0.06
Overall satisfaction	22.248	2	72.919	0.000	0.08
Perceived productivity	6.608	2	74.678	0.002	0.02

Table 11. Post hoc results for overall comfort and satisfaction by three building types.

	Building type	Mean (M)	Mean differences (Md)
			1	2	3
Overall comfort	1	4.50	–	−0.455*	0.197
	2	4.04	0.455*	–	0.652*
	3	4.70	−0.197	−0.652*	–
	Total	4.16
Overall satisfaction	1	4.41	–	−0.588*	0.200
	2	3.82	0.588*	–	0.788*
	3	4.61	−0.200	−0.788*	–
	Total	3.96
Perceived productivity	1	4.48	–	−0.263	0.192
	2	4.22	0.263	–	0.455*
	3	4.68	−0.192	−0.455*	–
	Total	4.30