Water Supples Flashcards

Question

Penstock and Flumes

Answer 1

``` • A flume is a channel where water flows • A penstock is an enclosed structure or pipe Rivers or lakes may be used if they are acceptable to authorities there has to be a record of non drought conditions for10 years ```

Answer 2

NFPA states that water supply connections from penstocks, flumes, rivers and lakes shall be arranged to avoid mud and sediment. • These shall be provided with approved double removable screens or approved strainers in an approved manner • Pendants on return bends • The sprinkler installer must be familiar with his area of the work, which generally includes all piping: supply, discharge, overflow, drains, filling, heating, testing and alarms.

Answer 3

Corrosive water can create fracturing within the pipe or buildup of deposits leading to: • Reduced flow progressing to complete obstructions • Compromised sprinkler system • Pinhole Leaks

Answer 4

Electrolysis – breakdown via electricity • oxygen concentration cells – metals combined with oxygen = rust • galvanic corrosion – two dissimilar metals and an electrolyte (water) the more reactive (anode) breaks down quicker

Answer 5

Many factors can help influence the corrosion: • pH – measure of the acid or base of the water • Alkaline vs basic • oxidizing agents – reacting with oxygen • carbon dioxide – can create carbonic acid which corrodes steel • dissolved solids – allows for better conductivity -> galvanic corrosion • Temperature – faster electrochemical reactions • velocity of flow - scouring • Bacteria – bacteria colonies -> deposits • metal characteristics – higher electrode metals corrode slower • stray currents.

Answer 6

If the pH level is too high in water, it can cause deposit or scaling on the pipe walls. • If the pH level is too low, it can degrade the pipe and create pinhole leaks • A neutral pH level is 7 • Water mixes with almost anything • Raw water sources are particularly susceptible • May require water treatment • follow routine testing, and using preventative measures as recommended in the NFPA 25 Standard for the Inspection, Testing, and Maintenance

Answer 7

``` minimum every 5 years but risk analysis can establish a different frequency minimum four-point inspection: 1.system valve 2. riser 3. cross main 4. branch line ```

Answer 8

The pH of the water. • The amount of oxygen in the water. • The chemical makeup of the water. • The amount of galvanic corrosion from the use of dissimilar metals contained in or in contact with the piping system. • The temperature of the water. • The velocity/pressure of the water in the pipe.

Answer 9

1. Uniform corrosion or general corrosion: • A regular loss of a small quantity of metal over the entire area 2. Pitting: • Localized form of corrosion that results in holes or cavities in the metal, normally forms in the direction of gravity 3. Galvanic corrosion: • An electric potential exists between dissimilar metals in a conductive (corrosive) solution • cathode + and anode – 4. Crevice corrosion: • occurs within crevices and other shielded areas on metal surfaces exposed to a stagnant corrosive solution. 5. Selective leaching: • The selective removal of one element from an alloy by corrosion eg., dezincification 6. Erosion corrosion: • Corrosion resulting from the cumulative damage of electrochemical reactions and mechanical effects • grooves, gullies, waves, rounded holes, or valleys in a metal surface. 7. Environmental cracking • caused by mechanical stresses, embrittlement, or fatigue. 8. Integranular corrosion – • within the makeup metal there are grains, this attacks at the boundaries of the grains 9. Microbiologically influenced corrosion (MIC): • Corrosion initiated or accelerated by the presence and activities of micro-organisms, including bacteria and fungi.

Answer 10

corrosive monitoring must be part of the system maintenance bid package to prevent large losses due to unexpected pipe failures and sprinkler head false activation. • Monitor the system rather than wait for the leaks • Sonic Inspection • Wall thickness measurements. • Digital video show video https://youtu.be/BLQekdZg3Qs • Water samples • 3D laser scanner technology

Answer 11

``` The water purveyor ensures the water quality to the property • Pipes • Hydrants • Valves • Water treatment • monitoring ``` • The owner is responsible for the water within the property

Answer 12

• Investigate dry systems first • System can be considered ok if: • < ½ cup of scale, scale isn’t large enough to plug a sprinkler • Go to most likely locations, known obstructions, warm areas, low points… • Flow 2 ½” lines from cross mains, 1 ½” through branch lines • Use burlap bags to collect material • Flow until water clears • If a fire pump is on the system, let it flow

Answer 13

Coating the inside of the pipes. • Galvanized pipe on dry systems???? • Use of CPVC. • Flushing a system to help slow down corrosion • Biocide – fights against MIC • Chlorine – kills bacteria • Dielectric union – electrolysis prevention • Cathode protection – neutralizes electrical current • Rectifier – introduces DC current • Nitrogen – eliminates oxygen and therefore the oxidizing agent • Air dryers – removes moisture from the piping • Monitoring probes – monitors the level of corrosion • Langelier Saturation Index