North Dakota Administrative Code › Title 33.1 - Department of Environmental Quality › Article 33.1-14 - NORTH DAKOTA BOILER RULES › Chapter 33.1-14-05 - POWER BOILERS - EXISTING INSTALLATIONS › Section 33.1-14-05-14 - Feedwater valves and piping

Current through Supplement No. 393, July, 2024
1. Except
				for high temperature water boilers, the feed piping must be provided with a
				check valve near the boiler and a valve or cock between the check valve and the
				boiler. When two or more boilers are fed from a common source, there also must
				be a globe or regulating valve on the branch to each boiler located between the
				check valve and the source of supply. Whenever globe valves are used on feed
				piping, the inlet must be under the disk of the valve. On single boiler-turbine
				unit installations, the boiler feed shutoff valve may be located upstream from
				the boiler feed check valve.
2.
				When the supply line to a boiler is divided into branch feed connections and
				all such connections are equipped with stop-and-check valves, the
				stop-and-check valves in the common source may be omitted.
3. If a boiler is equipped with duplicate
				feed arrangements, each such arrangement must be equipped as required by these
				rules.
4. A combination
				stop-and-check valve in which there is only one seat and disk and a valve stem
				is provided to close the valve when the stem is screwed down must be considered
				only as a stop valve, and a check valve must be installed as otherwise
				provided.
5. Where an economizer or
				other feedwater-heating device is connected directly to the boiler without
				intervening valves, the feed valves and check valves required must be placed on
				the inlet of the economizer or feedwater-heating device.
6. The recirculating return line for a
				high-temperature water boiler must be provided with the same stop valve, or
				valves, required by subsection 1 of section 33.1-14-05-13 for the main boiler
				and the required stop valve or valves is optional. A check valve may not be a
				substitute for a stop valve.
7.
				Except as provided for in subsections 8 and 10, boilers having more than five
				hundred square feet [46.45 square meters] of water-heating surface must have at
				least two means of feeding water. Each source of feeding must be capable of
				supplying water to the boiler at a pressure of six percent higher than the
				highest setting of any safety valve on the boiler. For boilers that are fired
				with solid fuel not in suspension, and for boilers whose setting or heat source
				can continue to supply sufficient heat to cause damage to the boiler if the
				feed supply is interrupted, one such means of feeding must not be subject to
				the same interruption as the first method.
8. Except as provided for in subsection 7,
				boilers fired by gaseous, liquid, or solid fuel in suspension may be equipped
				with a single means of feeding water provided means are furnished for the
				immediate shut off of heat input if the water feed is interrupted.
9. For boilers having a water-heating surface
				of not more than one hundred square feet [9.29 square meters], the feed piping
				and connection to the boiler may not be smaller than one-half inch [12.7
				millimeter] pipe size. For boilers having a water-heating surface more than one
				hundred square feet [9.29 square meters], the feed piping and connection to the
				boiler may not be less than three-quarter inch [19.05 millimeter] pipe
				size.
10. High-temperature water
				boilers must be provided with means of adding water to the boiler or system
				while under pressure.
11. The
				feedwater must be introduced into a boiler in such a manner that the water will
				not be discharged directly against surfaces exposed to gases of high
				temperature or to direct radiation from the fire or close to any riveted joints
				of the furnace sheets or of the shell. For pressures of four hundred pounds
				[2757.92 kilopascals] or over, the feedwater inlet through the drum must be
				fitted with shields, sleeves, or other suitable means to reduce the effects of
				temperature differentials in the shell or head. If necessary, the discharge end
				of the feed piping must be fitted with a baffle to divert the flow from riveted
				joints. Feedwater may not be introduced through the blowoff.
General Authority:
NDCC 23.1-16
Law Implemented:
NDCC
					 23.1-16