User guide

Application Guide | Gas detection in refrigeration systems
10 DKRCI.PA.S00.A1.02 | 520H12772 © Danfoss | DCS (MWA) | 2018.05
Requirements for gas detection
according to ASHRAE 15-2016
(USA)
Requirements for gas detection according
to ASHRAE 15-2016 state requirements for
rooms with refrigerating equipment including
machinery rooms. The “Low Level” alarm values
are less or equal to TLV-TWA levels.
Fig. 6: Gas detection requirements according to ASHRAE 15-2016.
* Note 1: The charge limit stated in ASHRAE 15-2016 can also be found in Annex II (RCL) - for selected refrigerants.
Note 2: ASHRAE 15 does not include Ammonia. Refer to ANSI/IIAR-2.
F-Gas legislation The F-Gas Regulation (EC) No 517/2014
One objective of the F-Gas Regulation is to
contain, prevent and thereby reduce emissions
of fluorinated greenhouse gases covered by the
Kyoto Protocol. The F-gas directive is mandatory
in all EU member countries and in the three
European Economic Area (EEA) EFTA countries
including Iceland, Liechtenstein, and Norway.
The regulation covers, among other topics, the
import, export and use of the traditional HFCs
and PFCs in all their applications. The regulation
entered into force on January 1
st
, 2015.
Leakage checking requirements, to prevent
leakage and to repair any detected leakage,
depends on the CO
2
equivalents of the refrigerant
in each circuit with refrigerant. The CO
2
equivalents is the charge in kg x the GWP of the
refrigerant.
A periodical leakage check by certified personnel
is required with the following frequency,
depending on the quantity used:
• 5 tCO
2eq
or more: At least once every 12 months
– except for hermetically sealed systems
containing less than 10 tCO
2eq
• 50 tCO
2eq
or more: At least once every 6 months
(12 months with an appropriate leakage
detection system)
• 500 tCO
2eq
or more: At least once every 6
months. An appropriate leakage detection
system is mandatory. The leakage detection
system must be checked at least once every 12
months.
In practice, the Occupational Exposure Limit
(OEL) values from ASHRAE 34 are used since they
are based on TLV-TWA (see also “Occupational
Exposure Limits”, page 18)
Requirements for gas detection
according to ANSI/IIAR-2 (USA)
ANSI/IIAR -2 requires machinery rooms to be
provided with ammonia gas detectors. It requires
3 different alarm levels (25, 150 and 40000 ppm)
with different response requirements according
to each of the levels.
Fig. 7: Gas detection requirements according to the ANSI/IIAR-2
(Clause 7.2)
(Clause 8.11.2.1)
(Clause 7.2)
(Clause 7.2.2)
N
N
Y
Start
Machinery
room
N
Gas detection
required
Charge >
RCL
N
Charge < 3 kg
No requirements
Y
No requirements
Y
Additional
requirements
Gas detection
required
Y N
Start
Machine room
Gas detector required
Alarm at 25 ppm
Gas detector required
Alarm at 25, 150,
and 40000 ppm (max)