Power Piping and Ammonia Refrigeration Systems Code Study Guide

Comprehensive fill-in-the-blank review flashcards covering Chapter 5230, ASME B31.1, ASME Section I power piping requirements, and ASME B31.5 ammonia refrigeration codes.

For power piping systems operating at temperatures over $750^\circ\text{F}$, __________ are recommended instead of standard bolts.

Bolt studs

In ASME B31.1 power piping systems, threaded joints are strictly prohibited at temperatures above __________.

$$925^\circ\text{F}$$

For steam service over $250\,\text{psi}$ or water service over $100\,\text{psi}$ and $220^\circ\text{F}$, the pipe shall be seamless, have a minimum ultimate tensile strength of $48,000\,\text{psi}$, and have a weight at least equal to __________.

Schedule 80

Brazed socket-type joints for valves and fittings must be made with suitable brazing alloys having melting points above __________.

$$840^\circ\text{F}$$

For all piping lines under pressure and above $250^\circ\text{F}$, gaskets are recommended to be metallic, asbestos, or other __________.

nonburning material

Pipe type prohibited in high-pressure steam or heating media systems

Furnace butt-welded pipe (Grade F)

Copper pipe, copper tubing, and brass pipe may be used for power piping service provided the operating temperature does not exceed __________.

$$406^\circ\text{F}$$

When steam pipes pass through combustible partitions, floors, or walls, metal sleeves must provide an all-around clearance of not less than __________ under hot and cold conditions.

$$1/4\,\text{inch}$$

By definition, a slow-opening valve requires at least __________ of the operating mechanism to change from fully closed to fully opened.

five $360^\circ$ turns

Outside screw and yoke (OS&Y) stem design is mandatory for threaded stem valves of size __________ and larger for pressures above $600\,\text{psi}$.

NPS 3

Minimum pipe schedule and construction required for bypasses lines

Must be at least Schedule 80 seamless, and may be integral or attached.

Following erection, all power piping systems must be capable of withstanding a hydrostatic test pressure of __________ the design pressure continuously maintained for at least $10\,\text{min}$.

$$1.5\,\text{times}$$

Piping systems are considered safe for occasional operation if pressure or temperature exceeds nominal design values by $15\%$ for no more than $8\,\text{hr}$ at any one time and not more than __________.

$$800\,\text{hr/year}$$

Piping systems are considered safe for occasional operation if pressure or temperature exceeds nominal design values by $20\%$ for no more than $1\,\text{hr}$ at any one time and not more than __________.

80 hours/ year

Boiler blowoff piping must be capable of withstanding the maximum allowable working pressure of the boiler by either $225\,\text{psi}$ or __________, whichever is less.

$$25\%$$

Required routing and bend specifications for pipe connections between a boiler and a blowoff tank

Must be made as direct as possible using sweep bends having a radius of $3$ times the diameter of the pipe.

Component required to connect the outlet piping with the vent pipe on a boiler blowoff tank

A $\frac{3}{4}\text{ in}$ siphon breaker

Boiler blowoff tank vent sizing ratio relative to the inlet or outlet size

Equal to $2.5$ times the size of the inlet or outlet

Before discharging into a sanitary sewer, boiler blowoff must pass through a blowoff tank or apparatus that reduces the pressure to not more than $5\,\text{pounds}$ and the temperature to not more than __________.

$$140^\circ\text{F}$$

Blowoff tanks must be installed with a clearance space of not less than $12\,\text{inches}$ between the tank and the floor, and not less than __________ between the tank and the wall.

$$18\,\text{inches}$$

Boilers having more than __________ of water heating surface shall be provided with at least two means of feeding water.

$$500\,\text{square feet}$$

Minimum delivery pressure required for each boiler feedwater source

$3\%$ higher than the highest setting of any safety valve on the boiler

Feedwater supply requirement for boilers fired with solid fuel not in suspension

Must be provided with at least two means of feeding water that cannot be subject to the same type of interruption (commonly accomplished by making one source steam-operated).

Boiler feed line valve arrangement and globe valve flow direction

The feed pipe must be equipped with a check valve and at least $1$ feedwater valve (stop valve, globe valve, or plug cock) placed between the check valve and the boiler. When a globe valve is used, the water inlet must enter under the disk.

Feedwater piping and valves between the feed pump and the boiler must meet or exceed the MAWP of the boiler by $225\,\text{psi}$ or __________ the MAWP, whichever is lesser.

$$1.25\,\text{times}$$

The temperature in degrees Fahrenheit of saturated steam can be approximated from gauge pressure using the formula: __________ plus $198$.

$$(\sqrt{\text{psig}}) \times 14$$

The suggested steel pipe support spacing in Table 121.5 is based on a fixed beam support with a maximum bending stress not exceeding __________.

$$2,300\,\text{psi}$$

Threaded hanger rods used for supporting pipe of nominal size $2\,\text{inch}$ and smaller must not be less than __________ in diameter.

$$3/8\,\text{inch}$$

The steam gage valve must be fitted with a tee or lever handle arranged to be __________ when the valve is open.

parallel to the pipe

Under ASME BPE standards, equipment parts subjected to Steam in Place (SIP) should withstand continuous flow of saturated steam at a minimum temperature of $266^\circ\text{F}$ for a minimum duration of __________ under steady-state conditions.

$$100\,\text{hr}$$

The Permissible Exposure Limit (worker exposure) of ammonia in refrigeration systems is __________.

$$50\,\text{parts per million}$$

At atmospheric pressure, the flammable limits of ammonia vapor by volume in air are __________.

$$15\% \text{ to } 28\%$$

In a restricted ammonia machinery room, no permanently installed flame-producing device or hot surface above __________ is permitted.

$$800^\circ\text{F}$$

Components in direct contact with ammonia must not contain copper, brass, zinc, __________, or alloys of these materials.

mercury

If an ammonia refrigeration system has any component designed for operating temperatures below __________, the piping must meet ASME B31.5 impact test requirements.

$$-20^\circ\text{F}$$

For carbon steel welded ammonia piping, pipe sizes of $1\,1/2\,\text{inch}$ and smaller must be __________.

Schedule 80

In public hallways or lobbies of commercial occupancies, ammonia piping systems are restricted to containing not more than __________ of refrigerant.

$$3.3\,\text{pounds}$$

Ammonia piping crossing an open passageway in a building must be installed at least __________ above the floor, unless positioned against the ceiling.

$$7.25\,\text{feet}$$

The storage tank capacity for anhydrous ammonia must be limited to __________ of water weight capacity at $60^\circ\text{F}$.

$$56\%$$

Refrigerant piping with a surface temperature of $140^\circ\text{F}$ or higher that is located less than __________ high or near passageways must be insulated or guarded.

$$7.25\,\text{ft}$$

In ammonia refrigeration piping systems, all joints larger than $2\,\text{inch}$ NPS must be __________.

welded

The discharge termination of an ammonia relief valve to atmosphere must be at least $15\,\text{feet}$ above ground and at least __________ from any window, ventilation intake, or personnel exit.

$$20\,\text{feet}$$

An ammonia pressure vessel of __________ or more internal gross volume must be protected by two parallel pressure relief devices connected to a three-way type stop valve.

$$103\,\text{feet}^3$$

Beyond the system charge itself, the maximum weight of refrigerant stored in an ammonia machinery room receiver must not exceed __________.

$$330\,\text{pounds}$$

Ammonia compressors driven by motors exceeding __________ must be equipped with antirecycle timers to prevent short cycling and overheating.

$$250\,\text{horsepower}$$

On an ammonia pipe marker conforming to ANSI A13.1 guidelines, the physical state section is printed in sky blue for vapor and in __________ for liquid.

yellow

On an ammonia pipe marker, an operating pressure exceeding __________ is classified as high pressure and printed in black letters on a red band.

$$70\,\text{psig}$$

Quarter-turn valves may be utilized in ammonia refrigeration service provided they feature an actuator with a minimum operating stroke duration of __________.

$$60\,\text{seconds}$$

Emergency mechanical ventilation systems in an ammonia machinery room must supply at least $30\,\text{ACH}$ and be actuated automatically by a refrigerant detector set at __________.

$$150\,\text{ppm}$$