260 R.I. Code R. 260-RICR-30-10-2.8

Current through December 3, 2024

Section 260-RICR-30-10-2.8 - EXISTING INSTALLATION: PRESSURE VESSELS

2.8.1 EPV-1 Maximum Allowable Working Pressure for Standard Pressure Vessels

The maximum allowable working pressure for standard pressure vessels shall be determined in accordance with the applicable provisions of the edition of the ASME Code or the API-ASME Code under which they were constructed and stamped.

2.8.2EPV-2 Maximum Allowable Working Pressure for Nonstandard Pressure Vessels, Except as Provided in § 2.8.3 of this Part.

A. The maximum allowable working pressure of a nonstandard pressure vessel shall be determined by the strength of the weakest course computed from the thickness of the plate, the tensile strength of the plate, the efficiency of the longitudinal joint, the inside diameter of the course and the factor of safety set by these rules.

1. TStE = maximum allowable working pressure, psi

2. DDDD

3. RFS

4. where:

a. TS = specified minimum tensile strength of shell plate material, psi. (When the tensile strength of carbon steel plate is not known, it may be taken as 55,000 psi for temperatures not exceeding 650 degrees Fahrenheit. For other materials use the lowest stress values for that material from Section VIII.)

b. t = minimum thickness of shell plate of weakest course, inches.

c. E = efficiency of longitudinal joint depending upon construction.

(1) for riveted joints - calculated riveted efficiency; for fusion-welded and brazed joints - the following percentages apply:

(AA)	Single lap weld	40%
(BB)	Double lap weld	50%
(CC)	Single butt weld	60%
(DD)	Double butt weld	70%
(EE)	Forge weld 70%
(FF)	Brazed steel 80%

d. R = inside radius of weakest course of shell, (inches) provided the thickness does not exceed 10 percent of the radius. If the thickness is over 10 percent of the radius, the outer radius shall be used.

e. FS = factor of safety allowed by these rules.

B. The minimum factor of safety in no case be less than 5 for existing installations. The working pressure shall be decreased when deemed necessary by the inspector to insure the operation of the vessel within safe limits. The condition of the vessel and the particular service to which it is subject will be the determining factors.

C. The maximum allowable working pressure permitted for formed heads under pressure shall be determined by using the appropriate formulas from 2017 ASME Code Section VIII, Division 1, and the tensile strength and factors of safety given in §§ 2.8.1 and 2.8.2 of this Part

D. The maximum allowable working pressure for nonstandard pressure vessels subjected to external pressure shall be determined by the rules of Section VIII, Division 1, of the 2017 ASME Code.

2.8.3EPV-3 Nonstandard Pressure Vessels - Use of Other Formulas

Pressure vessels that were not ASME Code stamped but which were constructed of known materials and were designed and constructed in accordance with sound engineering standards, formulas, and practices that provide safety equivalent to the intent of the Code shall be calculated on the same basis as used in the original design.

2.8.4EPV-4 Inspection of Inaccessible Parts

Where, in the opinion of the inspector, as the result of conditions disclosed at the time of inspection, it may be necessary to remove interior or exterior lining, covering or brickwork to expose certain parts of the vessel not normally visible, the owner or user shall remove such material to permit proper inspection and to determine remaining thickness.

2.8.5EPV-5 Overpressure Protection

Each pressure vessel shall be provided with pressure relief devices indicating and controlling devices as necessary to protect against overpressure. These devices shall be so constructed, located and installed that they cannot readily be rendered inoperative. The relieving capacity of such pressure relief device shall be adequate to prevent a rise in pressure in the vessel of more than 10 percent or 3 psi, whichever is greater, above the maximum allowable working pressure except when multiple relieving devices are provided, they shall prevent the pressure from rising more than 16 percent or 4 psi, whichever is greater above the maximum allowable working pressure. When multiple pressure relieving devices are provided, at least one device shall be set at or below the maximum allowable working pressure and the additional devices shall be set no higher than 105% of the maximum allowable working pressure. Where an additional hazard is involved due to fire or other unexpected sources of external heat, the pressure relief devices shall meet the requirements of ASME Code Section VIII, Division, paragraph UG-125 or Division 2, paragraph AR-130, whichever is applicable.

2.8.6EPV-6 Repairs and Renewals of Fittings and Appliances

Whenever repairs are made to fittings and appurtenances or it becomes necessary to replace them, the work must comply with the requirements for new installations.

260 R.I. Code R. 260-RICR-30-10-2.8

Amended effective 4/28/2019