Essay On Fire Sprinkler

Abbreviations

1. Chlorinated Polyvinyl Chloride - CPVC

2. National Fire Protection Association – NFPA

Introduction

The National Fire Protection Association (NFPA) lists four materials that can be used for fire sprinkler piping:-

• Steel

• Copper

• Polybutylene

• Chlorinated Polyvinyl Chloride (CPVC)

For this report only steel and CPVC is considered.

Steel versus CPVC pipes

How a fire sprinkler pipe degrades, both under long- term ambient conditions and when exposed to a fire, is an important consideration. Fire sprinkler system piping must remain structurally reliable for several decades and be able to withstand fire conditions to deliver water to the sprinkler heads. Material dgradation includes:-

1. Corrosion, scale build- up and sedimentation

These are;

i. Oxygen availability ii. Presence of sediment debris iii. Galvanic couples (electrochemical action that is produced by the reaction of two dissimilar metals that are in contact)

Fresh oygen is availed to the system only during flushing. This oxygen is quickly used up to corrode the pipe through oxidation. Once the oxygen is consumed, no more corrosion takes place within the pipe until the next flushing. The layer of oxide formed from the first supply of oxygen in the pipe retards additional corrosion from occuring each time fresh water is introduced into the system. The pipes can be coated with zinc to reduce the detrimental effects of rust. Zinc is more reactive than steel thus the oxygen reacts with it to form an oxide of zinc which now acts as the protective layer, thus protecting the steel.

It should be noted that dry- pipe sprinkler system is affected more by issues of rusting and corrosion since the pipe is not totally dry due to the little amount of water left within the pipe during testing of the system. Also, the quantity of oxygen in the dry pipe is more than that found in a wet pipe system. In our case, we are using a wet pipe