Boilers are essentially shell-and-tube heat exchangers, with water being boiled to steam or transformed to high pressure hot water. Heat is generated by burning a fossil fuel; the combustion gas can be ducted around tubes containing the water (water-tube boiler), or the hot gas can pass inside the tubes with the water being in the shell (fire-tube boiler). Stationary boilers, the very large boilers used in power generating stations, operate at high pressures and are invariably of the water-tube type. Water-tube designs are also popular for packaged boilers because they can be designed for higher pressure. Fire-tube boilers are limited to about 2.4 Mpa (350 psig) pressure and are used primarily for heating and process steam applications. This chapter provides information on a variety of topics that are useful for process engineers who are involved with the design, installation, or troubleshooting of a boiler system.

IBR boilers means any closed vessel exceeding 25 liters in capacity and which is used expressively for generating steam under pressure and includes any mounting or other fitting attached to such vessel which is wholly or partly under pressure when the steam is shut off. IBR steam pipe means any pipe through which steam passes from a boiler to a prime mover or other user or both if pressure at which steam passes through such pipes exceeds 3.5 kg/cm2 above atmospheric pressure or such pipe exceeds 254 mm in internal diameter and includes in either case any connected fitting of a steam pipe.

NON-IBR Boiler is a boiler which is not covered under Indian Boiler Regulation. Any boiler, which is not covered under IBR . a steam producing vessel whose volumetric capacity is less than 5 gallons (25 liters) is a Non-IBR Boiler & produces steam below one kilogram per centimeter square design gauge pressure.

• Outside the purview of IBR
• No registration of boiler required at the site
• Ease of operation & Maintenance