12
3.5 Refrigerant Charge and Room
Area Limitations
In UL/CSA 60335-2-40, R454B refrigerant is classified
as class A2L, which is mildly flammable. Therefore,
R454B refrigerant is suitable for systems needing
additional refrigerant charge and which will limit the area
of the rooms being served by the system.
Similarly, the total amount of refrigerant in the system
shall be less than or equal to the allowable maximum
refrigerant charge. The allowable maximum refrigerant
charge depends on the area of the rooms being served
by the system.
3.5.1 The room area calculation
requirements
The space considered shall be any space which
contains refrigerant-containing parts or into
which refrigerant could be released.
The room area (A) of the smallest, enclosed,
occupied space shall be used in the determination
of the refrigerant quantity limits.
The nouns in this section are explained as
follows:
Mc: The actual refrigerant charge in the system.
A: the actual room area where the appliance is
installed.
Amin: The required minimum room area.
Mmax:
The allowable maximum refrigerant charge
in a room.
Qmin : The minimum circulation airflow.
Anvmin：
The minimum opening area for connected
rooms.
TAmin：The total area of the conditioned space
(For appliances serving one or more rooms with
an air dut system).
TA：The total area of the conditioned space
connected by air ducts.
NOTE
CAUTION
Room height must be greater than 2.2m.
CAUTION
For determination of room area (A) when used to
calculate the refrigerant charge limit, the following shall
apply.
The room area (A) shall be defined as the room area
enclosed by the projection to the base of the walls,
partitions and doors of the space in which the appliance
is installed.
Spaces connected by only drop ceilings, ductwork, or
similar connections shall not be considered a single
space.
Units mounted higher than 70-55/64 inches and spaces
divided by partition walls that are no higher than
62-63/64 inches shall be considered a single space.
Rooms on the same floor and connected by an open
passageway between the spaces can be considered a
single room when determining compliance to Amin, if the
passageway complies with all of the following.
1) It is a permanent opening.
2) It extends to the floor.
3) It is intended for people to walk through.
The area of the connected rooms, on the same
floor,connected by permanent opening in the walls
and/or doors between occupied spaces, including gaps
between the wall and the floor, can be considered a
single room when determining compliance to Amin,
provided all of the following conditions are met as Fig.
3-3.
1) Low level opening
①The opening shall not be less than Anvmin in Table
3-1.
②The area of any openings above 11-13/16 inches from
the floor shall not be considered in determining
compliance with Anvmin.
③At least 50 % of the opening area of Anvmin shall be
below 7-7/8 inches from the floor.
④The bottom of the opening is not more than 3-15/16
inches from the floor.
⑤The opening is a permanent opening that cannot be
closed.
⑥For openings extending to the floor the height shall
not be less than 25/32 inches above the surface of the
floor covering.
2) High level opening
①The opening shall not be less than 50 % of Anvmin in
Table 3-1.
②The opening is a permanent opening that cannot be
closed.
③The opening shall be at least 59 inches above the
floor.
④The height of the opening is not less than 25/32
inches.
3）Room size requirement
①The room into which refrigerant can leak, plus the
connected adjacent room(s) shall have a total area not
less than Amin. Amin is shown in Table 3-3.
②The room area in which the unit is installed shall be
not less than 20 % Amin. Amin is shown in Table 3-3.
The requirement for the second opening can be
met by drop ceilings, ventilation ducts, or similar
arrangements that provide an airflow path
between the connected rooms.
NOTE
To Next Page
Loading...
