1.B.2.c - Venting and Flaring

Category Code Method AD EF
1.B.2.c T2 AS CS
Key Category NOx NMVOC SO2 NH3 PM2.5 PM10 TSP BC CO PB Cd Hg Diox PAH HCB
1.B.2.c -/- -/- -/- - -/- -/- -/- -/- -/- - - -/- - - -


Click to view Legend

Click to hide Legend

T = key source by Trend L = key source by Level

D Default
RA Reference Approach
T1 Tier 1 / Simple Methodology *
T2 Tier 2*
T3 Tier 3 / Detailed Methodology *
CS Country Specific
M Model
* as described in the EMEP/CORINAIR Emission Inventory Guidebook - 2007, in the group specific chapters.
AD - Data Source for Activity Data
NS National Statistics
RS Regional Statistics
IS International Statistics
PS Plant Specific data
AS Associations, business organisations
Q specific questionnaires, surveys
EF - Emission Factors
D Default (EMEP Guidebook)
C Confidential
CS Country Specific
PS Plant Specific data


Pursuant to general requirements of the Technical Instructions on Air Quality Control TA Luft (2002), gases, steam, hydrogen and hydrogen sulphide released from pressure valves and venting equipment must be collected in a gas-collection system. Wherever possible, gases so collected are burned in process combustion. Where such use is not possible, the gases are piped to a flare. Flares used for flaring of such gases must fulfill at least the requirements for flares for combustion of gases from operational disruptions and from safety valves. For refineries and other types of plants in categories 1.B.2, flares are indispensable safety components. In crude-oil refining, excessive pressures can build up in process systems, for various reasons.

Such excessive pressures have to be reduced via safety valves, to prevent tanks and pipelines from bursting. Safety valves release relevant products into pipelines that lead to flares. Flares carry out controlled burning of gases released via excessive pressures. When in place, flare-gas recovery systems liquify the majority of such gases and return them to refining processes or to refinery combustion systems. In the process, more than 99 % of the hydrocarbons in the gases are converted to CO2 and H2O. When a plant has such systems in operation, its flarehead will seldom show more than a small pilot flame.

Table 1: Activity data applied for 1.B.2.c

Unit 1990 1995 2000 2005 2010 2015 2020 2021
Flared natural gas millions of m³ 36 33 36 18.7 12.1 10.5 14.1 11.1
Refined crude-oil quantity millions of t 107 96.5 107.6 114.6 95.4 93.4 84.0 84.1

Flaring takes place in extraction and pumping systems and at refineries. In refineries, flaring operations are subdivided into regular operations and start-up / shut-down operations in connection with disruptions.

Table 2: Emission factors applied for flaring emissions in natural gas extraction, in [kg/ 1000 m3]

NMVOC 0.005
NOx 1.269
SO2 8.885
CO 0.726

Table 3: Emission factors applied for flaring emissions at petroleum production facilities

Unit Value
NOx kg/t 0.008
SO2 kg/t 0.010
CO g/t 0.1

Table 4: Emission factors applied for flaring emissions at at refineries: normal flaring operations

Unit Value
NMVOC kg/m³ 0.004
CO kg/m³ 0.001
SO2 kg/m³ 0.003
NOx g/m³ 0.4

Table 5: Emission factors applied for flaring emissions at at refineries: disruptions of flaring operations, in [kg/t]

NMVOC 0.001
CO 0.001
SO2 0.007
NOx 0.004

The emission factors have been derived from the 2004 and 2008 emissions declarations Theloke et al. 2013 1). In 2019, they were updated for CH4, N2O, CO, NMVOC, NOx and SO2, on the basis of Bender & von Müller, 2019 2).

Venting emissions are taken into account in category 1.B.2.b.iii. The SO₂ emissions are obtained from the activity data for the flared natural gas (Table 178) and an emission factor of 0.140 kg / 1,000 m³, a factor which takes account of an average H₂S content of 5 % by volume. The emission factors are determined on the basis of emissions reports, crude-oil-refining capacity and total capacity utilisation at German refineries. The guide for this work consists of the evaluation assessment of Theloke et al. (2013) 3).


For more details please refer to the super-ordinate chapter 1.B - Fugitive Emissions from fossil fuels

Planned improvements

Currently no improvements are planned.


1), 3) Theloke, J., Kampffmeyer, T., Kugler, U., Friedrich, R., Schilling, S., Wolf, L., & Springwald, T. (2013). Ermittlung von Emissionsfaktoren und Aktivitätsraten im Bereich IPCC (1996) 1.B.2.a. i-vi - Diffuse Emissionen aus Mineralöl und Mineralölprodukten (Förderkennzeichen 360 16 033). Stuttgart.
2) Bender, M., & von Müller, G. (2019). Konsolidierung der Treibhausgasemissionsberechnungen unter der 2. Verpflichtungsperiode des Kyoto-Protokolls und der neuen Klimaschutz-Berichterstattungs-pflichten an die EU (FKZ 3716 41 107 0).