Module 10. Steam generators

Lesson 26


26.1  Objectives of Indian Boiler Regulation Act

Indian Boiler Regulation act is made to encompass the following

1.      Provide for the safety of life, limb and property.

2.      Create a board for boiler rules to serve the society.

3.      Formulate rules and regulations for the safe and proper construction, installation, repair, use and operation of boilers and unfired pressure vessel.

4.      Provide for the examination and appointment of boiler inspectors.

5.      Provide for the inspection of boiler and unfired pressure vessel, the fees to be charged and the reports to be made thereof.

6.      Provide for the enforcement of the rules and regulations promulgated by the board of boiler rules.

7.      Provide for inspection certificate.

8.      Provide for appeals.

9.      Provide a penalty for the violation of the provisions of the act.

The boiler being pressure vessel is required to be operated within safe pressure limits with regular checkup and maintenance, because the failure of a boiler may prove extremely disastrous. To ensure full safety, some standard rules and regulations have been enforced through legislation, all over the country. This is known as Indian Boiler Act 1923. All boilers owners are required to follow this legislation in a strict sense. The main provisions of the act are

a)      Registration with chief inspector of boilers.

b)      Determination of maximum working pressure by the boiler inspector and obtaining a certificate.

c)      Reporting to authority in case of accident within 24 hours.

d)     Periodic check-up by boiler inspector

26.2  The Administrative Regulations and Rules stipulate the following

Boilers are to be constructed, inspected and stamped in conformity with Indian Boiler regulation act of boiler and pressure vessel code.

  1. Inspection certificate is to be in accordance with central boiler board.
  2. Inspection and testing procedures must be in conformity with central board.
  3. Repairs, new parts or replacements are to be in conformity with central board.
  4. Miscellaneous provisions are to be in conformity with central board.

26.3  Boiler Inspection

The inspectors designated by each government carry out, normally, annual inspection. The inspection includes first check after the boiler is completely stripped to examine defective design if any or damage during transit under hydraulic pressure and issue of a certificate and a registration number. The hydraulic test checks the tightness of boiler joints, setting of leakage during repair, after completely filling with the pressure as 1.5 times the prescribed working pressure. For a new boiler of capacity less than 688 kPa, it is checked under double pressure. For new boilers over 688 kPa, the pressure applied is 1.5 times the working pressure plus 34 kPa for leak test.

The steam test is carried out to check the setting of safety valve at the working pressure and sealing the same. Inspection under steam is done in case where the boiler cannot be stopped for some reason. Internal inspection is done when internal parts like tubes are taken out from boiler for repair or renewal. To check the observance of rules, surprise inspections are also done. In case of accident the inspector holds an enquiry at site to assess the cause of accident and damage to boiler or personnel.

26.4  Boiler and Pressure Vessel Committee

The functions of the committee are the following

  1. To establish rule of safety governing (a) the design (b) the fabrication, and (c) the inspection of boilers and unfired pressure vessels during construction
  2. To interpret these rules when questions arise regarding their intent.

In formulation of the rules, the committee considers the needs of users, manufactures and inspectors of pressure vessels (fired and unfired). It deals with the care and inspection of boilers and pressure vessels in service only to the extent of providing suggested rules of good practice and aid to owners and their inspectors. The committee does not approve, recommend, comment on, nor endorse proprietary or specific design, nor does it assume to limit in any way, the builders right to choose any method of design or form of construction that conforms to the code rules.

26.5  Boiler and Pressure Vessel Code

The formulation of the rules of the Boiler and Pressure Vessel requires consideration of the following

  1. Maximum design and operating pressures
  2. Design formulae and computation methods, including (a) allowable working stresses, (b) strength of materials, and (c) minimum thickness of plates and tubes
  3. Construction specifications, including (a) material selection, (b) forming and fabrication techniques, and (c) fusion welding or riveting.
  4. Setting and installation requirements, including (a) method of support, and  (b) encasement
  5. Fitting and appliances, including (a) gases, (b) stop valves, (c) steam mains, (d) blow off and feel piping, and  (e) water columns and pipes
  6. Safety and relief valves, including (a) discharge capacity and rating, and (b) method of installation and piping.
  7. Hydrostatic tests inspection, and stamping
  8. Manufacture’s data report and inspection certificates.

As the primary object of the Boiler Code is safety, the interests of the users of boilers pressures vessels are of paramount importance. The rules have been formulated to afford reasonably certain protection of life and property while a unit is in service and to provide a margin for deterioration in service so as to given a reasonable, safe period of usefulness. The interests of the manufacturer have also been recognized by taking into consideration advance in design and materials as well as by honoring proof of his own experience.

The Boiler Code does not contain rules to cover all details of design and construction. When complete details are not given, it is intended that the manufacturer, subject to the approval of the authorized inspector, provide details of design and construction that will be as safe as those otherwise provided by the rules in the code.

26.6  National Board of Boiler and Pressure Vessel Inspectors

The National Board of Boiler and Pressure Vessel Inspectors represent the administrative agency for the ASME Boiler code as incorporated into various local or state laws. The voluntary organization consists of a Chief Inspector, or the official, charged with the enforcement of boiler and pressure vessel inspection regulations of any political subdivision that (1) maintains a duly constituted department bureau, or division for the purpose of enforcement of the Code; and (2) has adopted the ASME Boiler Code (in whole or in part).

26.6.1  The objects of the organization are the following

1)      Promoting uniform enforcement of boiler and pressure vessel laws and rules.

2)      Securing uniform approval of specific design and structural details of boiler and pressure vessels as well as appurtenances and devices instrumental in the safe operation of such vessels.

3)      Promoting one uniform code of rules for and one standard stamp to be placed on, all boilers and pressure vessels constructed in accordance with the requirements of that code.

4)      Promoting one standard of qualifications and examinations for inspectors who are to enforce the requirements of said code.

5)      Gathering and compiling data and statistics useful to the members in their enforcement work on such boiler laws and rules, and distributing these to the members.

6)      Promoting the use of uniform, standardized inspection reports.

The officials charged with the enforcement of the law must judge whether or not such legal requirements are complied with. It is their duty to protect the constituents within their jurisdiction against loss of life and property by requiring that boilers comply with certain regulations. However, they must also protect the rights of industries compelled to conform with adopted regulations that have the full effect of law.

When there are violations of the construction requirement of the law, two persons are involved- the manufacturer and the authorized inspector. The law provides a penalty for either or both such parties. For a violation the inspector’s certification and the manufacturer’s authorization to build boilers may both be revoked.

To promote uniformity in the administration of the law and the ASME Boiler Code, the National Board Certifies inspectors on the basis of uniform examinations and maintains laboratory facilities for testing safety and relief valves.

It also sponsors and publishes the following literature:

1.   “National Board Inspection Code”.

2.   “Rules for Repair”.

3.   “National Board Requirement for Inspection and Stamping”.

4.   “Manufactures Authorized Under the National Board”.

5.   “National Board Requirements for Boiler Blow-off Equipment”.

6.   “Safety Valves and Relief Valves Approved By the National Board.”

26.7  National Board Inspection Code

It is the policy of the National board not to make rules that differ from the ASME Boiler Code, and to accept, whenever possible, construction rules formulated by the Boiler Code Committee. As the objectives are mutual matters that pertain to the administration of the ASME boiler Code are referred to the National Board, and matters that pertain to construction rules are referred to the ASME Boiler and Pressure Vessel Code Committee.

To provide adequately for those matters that do not concern the construction of new boilers, the National Board Inspection Code has been promulgated. It obtains its effectiveness by being incorporated into various Board of boiler Rules “Regulations” authorized by legislation.

26.8  The Inspection code contains the following topics

1.      Purpose and Objectives

2.      Administration of Safety laws and Regulations

3.      Regulation of Existing Installation of Power Boilers

4.      Inspection of Existing Boilers and Pressure Vessels

5.      Inspection of New Boilers and or Pressure Vessels

6.      Repair to Boilers and Pressure Vessels

7.      Inspection of Fusion Welding in Fabrication

8.      Safety of Vessels on Low-Pressure side of Reducing Valve

9.      Fuel Cutoffs and Feed water-Regulating Devices for Boilers

26.9  General Requirements

A boiler shall not be registered and a certificate shall not be issued with reference to boiler unless the standard conditions in respect of material, design and construction are met namely.

·         When the material used in construction of boiler, steam pipe, economizer or super heater is not in conformity with Indian Boiler Regulation but is known to be commonly used in other countries as being suitable for use in construction of boilers and steam pipes; provided that such material is not specifically prohibited by regulations.

·         When constructional features of a boiler, steam pipe, economizer or super heater are not in conformity with the regulations but also are not considered by the board to be inferior in strength to those prescribed in regulations and form part of usual manufacturing practice of boiler and steam pipe in other countries.

·         When a boiler, steam pipe, economizer or super heater has been built in conformity with the regulations.

·         No structural part of a boiler, which is subject to pressure, shall be made of Bessemer Process Steel or of cast or malleable cast iron.

·         All plates and bars used in the construction of boiler shall be tested and found to conform to the regulations.

·         All boilers during construction shall be under the supervision of an inspecting officer and shall be inspected at all stages of construction

·         Welders engaged in site welding of boilers steam pipe, economizer or super heaters shall possess and produce to the satisfaction of the chief inspector.

·         A certificate from an inspecting authority certifying that material was tested and boiler was built under their supervision.

·         A certificate from manufacturer and test signed by the maker or by a responsible representative of the maker of boiler containing a description of boiler, its principle dimensions, particulars of the kind of material used in its construction, the thickness of a plate etc.

·         A drawing or print to scale, in case of large boilers of not less than ¾" to the foot and in case of small boilers of not less than to foot showing the principal dimensions and longitudinal section and end view of boiler.

·         A certificate from steel maker and a certificate from maker of plate rivet or bars.

·         In case of fusion welded and seamless forged drums and headers, a certificate from the manufacturer furnishing the result of tests in regard to  chemical analysis, tensile, bend and Izod impact test.

·         For tubes and pipes subjected to internal pressure, a certificate giving result of tests regarding chemical analysis, warm yield point, and the average stress to produce an elongation of 1% in 100,000 norms.

·          A certificate of manufacturer signed by the maker or a responsible representative of makers of steam pipes containing particulars and results of tests of the material used in the manufacture.

·         Under the regulations for determining the working pressure to be allowed on various parts of boiler, the material to which the formula apply.

26.10  Indian Boiler Regulation Cover

Chapter-I         On material of construction of steel plates, rivets, section and bars

Chapter-II       deals with construction and workmanship.

Chapter-III      Regulations for determining the working pressure to be allowed on various parts of boiler.

Chapter-IV      Fusion welded and seam less forged drums for water tube boilers and super heaters.

Chapter-V       Specification of valves, gauges and auxiliaries.

Chapter-VI      Deals with steam pipes and fittings

Chapter-VII    Regulations for registration and inspection of boilers.

Chapter-VIII   Instructions regarding safety of pressure working inside of boiler.

Chapter-IX      Instructions for electrode boiler.

Chapter-X       Standard conditions for the design and construction of economizer, feed pipes, feed heater and other similar vessels.

Chapter-XI      Shell type boiler of welded constructions.

Chapter-XII    Qualification tests for welders engaged in welding of boilers and steam pipe under constructions.

Chapter-XIII   Regulations prescribed for miniature boiler.

Chapter-XIV   For Heat Exchanger, converters, evaporators & similar vessels.