A proposed framework for measuring direct and indirect carbon emissions in the operational phase of a construction project: a case study

Figures & data

Figure 1. Main methodology diagram.

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A flowchart of 3 steps; starts by taking a questionnaire, then calculations, and then applying mitigation strategies.

Table 1. Organisation information.

Name of the organisation
Country of the organisation
The building number
The type of the building
Area per floor
Number of employees
Period of the report

Table 2. Questionnaire and data gathering for commuting.

do the organisation own/control vehicles?			Yes
Specify the number of employees.
Specify the number of employees using the bus.
Number of buses/vans	Capacity:	21
Average distance commuted in one bus route (km)
Specify the number of vehicles owned by employees.
Specify the number of vehicles/private cars.

Table 3. Questionnaire and data gathering of water usage.

Specify if you have a swimming pool and showers	Yes
Specify if you water a garden.	No
Specify the number of employees.
Specify the number of janitors.
Specify the number of cleaning laps.
Specify the amount of water supplied.
Specify the amount of water treated and reused.
Specify the number of garden watering laps.

Table 4. Questionnaire and data gathering of energy usage.

Specify total annual electricity consumption

Table 5. Questionnaire and data gathering of refrigerants.

do your organisation uses ACs/Heaters	Yes
Specify the type of equipment charged.
Specify the number of equipment charged.
Specify the type of refrigerant.
Specify the quantity of refrigerant.

Table 6. Commuting carbon footprint calculations.

Average Kilometers (km/L)	Fuel Type	fuel carbon emission (CO2/L)	Total distance (Km)	kg CO2e	MT CO2e
	Diesel	2.64
	Gasoline	2.392
	LPG	1.665
	Low-calorific CNG	2.252
	High-calorific CNG	2.666

Table 7. Electric cars’ carbon footprint calculations.

Fuel Type	Fuel Factor	Total distance	kg CO2e	MT CO2e
Battery electric car	0.05
Hybrid	0.12
Plug-in hybrid electric	0.1

Table 8. Water carbon footprint calculations.

Water supply: water derived through the main supply network
Type	Unit	Factor	Amount	kg CO2e	MT CO2e
Water supply	M^3	0.1490
Water treatment: Water returned into the sewage system through the main drains
Type	Unit	Factor	Amount	kg CO2e	MT CO2e
Water supply	M^3	0.2720

Table 9. Electricity carbon footprint calculations.

Electricity grid: Electricity used by an organisation at sites owned
Type	Unit	Factor	Amount	kg CO2e	MT CO2e
Electricity	kWh	0.53330

Table 10. Refrigerants carbon footprint calculations.

Refrigerant and others: From leakage of air-conditioning and refrigeration units
Emission	Unit	Factor	Amount	Kg CO2e	MT CO2e
HFC-134a= R134a	kg	1430
HCFC-22/R22 = chlorodifluoromethane	kg	1810
R410A	kg	2088

Table 11. Commuting carbon footprint reduction.

Total Amount of MT CO2e
Mitigation Strategies
1- Switch vehicles to a greener alternative, such as hybrid or electric vehicles
2- Schedule all the buses to have their full capacity to avoid buses with empty seats
3- Introduce a transportation application that encourages the idea of carpooling
4- provide drivers with training to show them the benefits of fuel-efficient journeys
5- Encourage employees by using public transportation

Table 12. Water carbon footprint reduction.

Total Amount of MT CO2e
Mitigation Strategies
1- Set up a water action plan with employees
2- Consider installing a greywater system for reusing water in flushing toilets and watering plants.
3- Install low-flow fixtures, such as dual flush toilets.
4- Always check for toilet leaks. Put a dye into the tank to appear in the bowl in case of leaking.
5- plant greenery that requires less water.
6- Keep swimming pools covered when not in use to avoid evaporation.
7- arrange seminars to raise awareness about water reduction
8- Save and reuse rainwater for watering gardens.

Table 13. Electricity carbon footprint reduction.

Total Amount of MT CO2e
Mitigation Strategies
1- Install motion and occupancy sensors in the rooms and corridors to automatically turn off the lights when it is not occupied.
2- Install energy-efficient light units.
3- Use renewable energy sources by using solar panels, especially on roofs and vast spaces.
4- Use a power strip to reduce plug loads.
5- Make sure appliances are energy efficient.
6- For landscape lighting, instal solar-powered devices.
7- Establish a set of bylaws requiring the students and staff to turn off unused equipment.
8- Create a reward system for the most minor electricity consumption departments.

Table 14. Refrigerants carbon footprint reduction.

Total Amount of MT CO2e
Mitigation Strategies
1- Maintain the air conditioning systems.
2- Always check for leakage from existing appliances.
3- Use a refrigerant gas with lower environmental impact: Use a refrigerant gas with zero ozone depletion potential (ODP) and low global warming potential (GWP).
4- Ensure correct end-of-life treatment of refrigerant gases.
5- Use refrigeration or air conditioning systems less often.
6- Ensure that AC/Heating systems are only operated in occupied rooms.

Figure 2. The whole framework diagram.

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A flowchart discussing the exact steps of following our framework.

Figure 3. Comparison between our framework and an existing similar framework.

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A flowchart discussing the steps of following two different frameworks.

Figure 4. The operational boundary of Nile University.

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The master plan of Nile University, where the study buildings are highlighted in yellow.

Table 15. Summary of activity data Collected.

Scope	Emission source	Activity Data	Quantity	Unit
Scope 1	Stationary Combustion	Diesel Fuel Consumption	1,500	Litres
	Mobile combustion	Motor Gasoline Consumption	3,774.51	Litres
		Diesel Fuel Consumption	14,248.06	Litres
	Fugitive emissions	Refrigerants (R- 22) charge	54.4	Kg
		Laboratories	179	gm CO2
Scope 2	Electricity	Electricity Consumption	4,107	MWh

Table 16. Breakdown of Scope 1 direct emission sources.

Emission Source Type	Emission Source in the Nile University	MT CO2e/Year
Stationary Combustion Sources	Generators	4.07
	Total	4.07
Mobile Sources	Owned buses	39.06
	Owned cars	8.82
	Total	47.88
Fugitive Emissions	A/C and refrigerants	9.57
	Laboratories	0.0002
	Total	9.57
Scope 1 – Direct Emissions Total		61.53

Table 17. Breakdown of Scope 2 indirect emission sources.

Emission Source Type	Emission Source in the Nile University	MT CO2e/Year
Electricity	-	2,188.02
Scope 2 – Indirect Emissions Total		2,1888.02

Table 18. Data gaps and recommendations.

Emission Source	Data Requirement	Applied Assumptions	Data Gap	Recommendation
Stationary fuel combustion (generators)	Fuel type Fuel quantity Fuel NCV Fuel density	DensityFuel NCV Fuel NCV	50%	Provide fuel density and NCV
Mobile fuel combustion – owned buses	Vehicle type Fuel type Fuel quantity Fuel NCV Fuel density	DensityFuel NCV Fuel NCV	40%	Provide fuel density and NCV
A/Cs and refrigerants	The type of equipment charged Number of equipment charges Type of refrigerant Quantity of refrigerant Operating emission rate	Operating emission rate	20%	Provide operating emission rate
Electricity consumption	Total electricity consumption Excluded electricity consumption	None	0%	None

Table 19. GHG emission intensity of NU.

Employees’ Share of Total GHG Emissions

As of 2021, Nile University employed 471 employees. Accordingly, each employee’s share of the total GHG emissions is 4.78 MT CO2e/employee/year.

Students’ Share of Total GHG Emissions

As of 2021, Nile University had 3,100 students. Accordingly, each student’s share of the total GHG emissions is 0.726 MT CO2e/student/year.

Building Space Share of Total GHG Emissions

With the three buildings (B1, B2 and B4) and hence, a total area of 54,000 m2, the share of the total GHG emissions per area is .042 MT CO2e/m2

Table 20. Benchmarking of NU GHG emissions against selected institutions of higher education.

University	Reporting Year	Emissions per Student (MT CO2e/student/yr)	Emissions per Unit Area (MT CO2e/m^2/yr)
Nile University (NU)	(2020–2021)	0.726	0.042
American University in Cairo (AUC)	(2019–2020)	3.8	0.122
American University in Sharjah (AUS)	(2018–2019)	11.35	0.045

Data availability statement

Data available on request.