Pressure vessels

[ngraj1]

Hi All,

I am looking for some information on pressure vessels.

What will be the minimum capacity and pressure requirements to call the equipment/pipie as a pressure vessel. I would appreciate if any one can share their thoughts and provide some reference if possible.

Cheers,
Raj

[Omar F. Hassan]

Dear
If you still interest about this subject
Contact me (omer_fh2003@yahoo.com)

[ali]

VESSEL:
A container or structural envelope in which materials are processed, treated, or stored; for example, pressure vessel, reactor vessel, agitator vessel, and storage vessels (tanks).

PRESSURE VESSEL:
A metal container generally cylindrical or spheroid, capable or withstanding various loadings.

What is a pressure vessel?
A pressure vessel is defined as�"a vessel in which the pressure is obtained from an indirect source or by the application of heat from an indirect source or a direct source. The vessel proper terminates at: (a) the first circumferential joint for welded end connections; (b) the face of the first flange in bolted flange connections; or (c) the first threaded joint in threaded connections." Pressure vessels include but are not limited to compressed gas storage tanks (i.e., air, oxygen, nitrogen tanks, etc.), anhydrous ammonia tanks, hydro pneumatic tanks, autoclaves, hot water storage tanks, chemical reactors and refrigerant vessels, designed for a pressure greater than 15 psi and a volume greater than 5 cubic feet in volume or one and one-half cubic feet in volume with a pressure greater than 600 psi.

North Carolina pressure vessel law
The North Carolina General Assembly first enacted a law instituting regulation of high-pressure boilers in 1935. Since then, legislation has been adopted to include low-pressure boilers and pressure vessels. In 1975, the General Assembly enacted the Uniform Boiler and Pressure Vessel Act, codified as Chapter 95, Article 7A, of the General Statutes.

What are the construction and installation requirements for my pressure vessel?
Hot water storage tanks installed after 1951 and all other pressure vessels installed after 1975, must be constructed to the applicable ASME Code requirements.
How often do I have to have my rressure vessel inspected?
Periodic inspection requirements are in the North Carolina Administrative Code, Title 13, Chapter 13, Paragraph .0211. They are:

Hydro pneumatic tanks - external inspections every five years.*
All other pressure vessels - external inspections every two years.*
Internal inspections are conducted if considered necessary by the inspector of record.

Who can legally inspect my pressure vessel?
North Carolina law allows for three types of pressure vessel inspectors. They are:

Boiler & Pressure Vessel Inspector - an employee of the North Carolina Department of Labor, Boiler Safety Bureau. Authorized to inspect any boiler or pressure vessel subject to the Uniform Boiler & Pressure Vessel Act.
Special Inspector - an employee of an insurance company authorized to underwrite in this State boiler and machinery insurance. Authorized to inspect only what their company insures.
Owner-User Inspector - an employee of a company operating boilers or pressure vessels, the company has an inspection program that is under the supervision of one or more engineers having qualifications satisfactory to and approved by the Commissioner of Labor.

All inspectors must:

Have passed an examination set by the National Board of Boilers and Pressure Vessel inspectors
Hold a certificate of competency issued by the National Board of Boiler and Pressure Vessel inspector
Hold a commission issued by the North Carolina Department of Labor.
Note: Any person who knowingly and willfully misrepresents himself as an authorized inspector in North Carolina is guilty of a Class 2 misdemeanor. (GS 95-69.18)

Why are pressure vessel inspections necessary?
Pressure vessels usually fail in a catastrophic manner, releasing vast stores of energy and contents. The results are manifold:

A shock wave of the vessel contents
High-speed projectiles

Either result can have devastating consequences. Pressure vessels and storage tanks can fall into several different categories, each with its own risk. However, the end result is:

Failure poses safety risk to personnel.
Failure may jeopardize other critical components.
Failure may result in the release of hazardous or toxic contents, Environmental pollution, or loss of production, may occur.

The potential dangers are major: For example, an 80-gallon air tank operating at 200 psi has the equivalence of 393 grams of TNT - enough force to destroy a average business and harm its employees. Inspections ensure that such accidents do not happen. Since inspections are a snapshot in time and can only determine how safe the vessel is at the time of the inspection, owners/operators must keep their pressure vessels properly maintained.

What is an inspection certificate and why do I need one?
The inspection certificate is evidence that the Boiler has been inspected and is safe to operate under the pressure and temperatures noted on the certificate.

North Carolina law states that no boiler or pressure vessel may be operated without a current inspection certificate, operating without a current certificate is considered a Class 3 misdemeanor.

Pressure vessel owner responsibilities
Under the state's Boiler Code, the owner's responsibilities include:

Obtaining periodic inspections provided by commissioned boiler inspectors with the North Carolina Department of Labor or with a boiler insurance company. Note: Inspectors are not responsible for scheduling inspections. Owners must ensure that a current Certificate of Inspection is in force.
Paying the required fees for the Certificate of Inspections.
Posting the current and valid Certificate of Inspection under a transparent cover in the boiler room. Obtaining proper repairs and involving the commissioned inspector in all repairs.
Notifying the Boiler Safety Bureau in the event of an accident.

What do I do about repairs to my pressure vessel?
The boiler and pressure vessels rules state that a repair company must be authorized to perform repairs by the National Board of Boiler and Pressure Vessel Inspectors and hold an "R" stamp.
In all cases, the owner and the repair company must consult an inspector before the repair is attempted. The completed repair is subject to the inspector's acceptance.

Is there a fee for the inspection?
The Boiler Safety Bureau is fee funded and does not receive any money from the legislature. Therefore, the Bureau charges a fee for its services. The fee is dependent upon the complexity of work and the time spent inspecting the object it ranges between $30 to $150 per object inspected. The fees cover the inspection activity, the maintenance of a data storage system and the issuance of the inspection certificate.

What do I do in the event of an accident?
A detailed report of the accident must be submitted to the Boiler Safety Bureau immediately (phone and fax number are provided in this pamphlet). In the event of personnel injury or any explosion, neither the vessel, nor any parts shall be removed or disturbed before permission has been given by the Chief Inspector, except for the purpose of saving human life and limiting consequential damage.