1534                                   LAWS OF MARYLAND                               Ch. 732

172.

(A)  THE PROVISIONS OF THIS SUBTITLE DO NOT APPLY TO THE
FOLLOWING BOILERS AND PRESSURE VESSELS:

(1)     BOILERS AND PRESSURE VESSELS UNDER FEDERAL
CONTROL OR REGULATION.

(2)    PRESSURE VESSELS USED FOR TRANSPORTATION AND
STORAGE OF COMPRESSED GASES WHEN CONSTRUCTED IN
COMPLIANCE WITH SPECIFICATIONS OF THE U.S. DEPARTMENT OF
TRANSPORTATION AND WHEN CHARGED WITH GAS MARKED,
MAINTAINED, AND PERIODICALLY REQUALIFIED FOR USE, AS
REQUIRED BY APPROPRIATE REGULATIONS OF THE U.S.
DEPARTMENT OF TRANSPORTATION.

(3)   AIR TANKS LOCATED ON VEHICLES OPERATING UNDER
THE RULES OF OTHER STATE AUTHORITIES AND USED FOR
CARRYING PASSENGERS OR FREIGHT.

(4)    AIR TANKS INSTALLED ON THE RIGHT OF WAY OF
RAILROADS AND USED DIRECTLY IN THE OPERATION OF TRAINS.

(5)  PRESSURE VESSELS THAT DO NOT EXCEED (A) 5 CU. FT. IN
VOLUME AND 250 PSIG PRESSURE; OR (B) 1 1/2 CU. FT. IN VOLUME
AND 600 PSIG PRESSURE; OR (C) AN INSIDE DIAMETER OF 6 IN.
WITH NO LIMITATION ON PRESSURE.

(6)  PRESSURE VESSELS OPERATING AT A WORKING PRESSURE
NOT EXCEEDING 15 PSIG.

(7)  VESSELS WITH A NOMINAL WATER-CONTAINING CAPACITY
OF 120 GAL. OR LESS FOR CONTAINING WATER UNDER PRESSURE,
INCLUDING THOSE CONTAINING AIR., THE COMPRESSION OF
WHICH SERVES ONLY AS A CUSHION.

(8)  HOT WATER SUPPLY BOILERS WHICH ARE DIRECTLY FIRED
WITH OIL, GAS OR ELECTRICITY WHEN NONE OF THE FOLLOWING
LIMITATIONS ARE EXCEEDED:

(I)  HEAT INPUT OF 200,000 BTU/HR.,

(II)  WATER TEMPERATURE OF 200F.,

(III)    NOMINAL WATER CAPACITY OF 120 GALS. THESE
EXEMPT HOT WATER SUPPLY BOILERS SHALL BE EQUIPPED WITH
SAFETY RELIEF VALVES.

(B)  THE FOLLOWING BOILERS AND PRESSURE VESSELS SHALL BE
EXEMPT FROM THE REQUIREMENTS OF SECTIONS 176, 177 AND 178
OF THIS SUBTITLE:

(1)  BOILERS OR PRESSURE VESSELS LOCATED ON FARMS AND
USED SOLELY FOR AGRICULTURAL PURPOSES.

(2)    HEATING BOILERS WHICH ARE LOCATED IN PRIVATE
RESIDENCES OR IN APARTMENT HOUSES OF LESS THAN SIX (6)
FAMILY UNITS.