distance between the rows, and 190 when P is taken to be the pitch between the stays in the rows. For steel plates, other than those for combustion chambers, the values of C may be increased as follows: C If flat plates are strengthened with doubling plates securely riveted to them, having a thickness of not less than 2/3 of that of the plates, the strength to be taken from working pressure in pounds, per square inch: where t equals thickness of doubling plates in sixteenths, and C, T, and P are as above. Note. In the case of front plates of boilers in the steam space, these numbers should be reduced to 20 per cent, unless the plates are guarded from the direct action of the heat. For steel tube plates in the nest of tubes the strength to be taken from Tthe thickness of the plates in sixteenths of an inch, P=the mean pitch of stay tubes from center to center. For the wide water spaces between the nests of tubes, the strength to be taken from сх т P -= working pressure in pounds per square inch, where Pthe horizontal distance from center to center of the bounding rows of tubes, and C where the stay tubes are pitched with two plain tubes between them and not fitted with nuts outside the plates. Cif they are fitted with nuts outside the plates. C if each alternate tube is a stay tube not fitted with nuts. Cif they are fitted with nuts outside the plates. Cif every tube in these rows is a stay tube and not fitted with nuts. Cif every tube in these rows is a stay tube and each alternate stay tube is fitted with nuts outside the plates. The thickness of tube plates of combustion chambers in cases where the pressure on the top of the chambers is borne by these plates is not to be less than that given by the following rule: T= PX W X D 1750 × (D-d) where P working pressure in pounds per square inch. W width of combustion chamber between plates in inches. d inside diameter of plain tube in inches. Tthickness of tube plates in sixteenths of an inch. The constants will be the constants adopted by the American society of mechanical engineers. 8052d2. Strength of rivets.-25. The strength of the rivet in shear compared to the solid plate shall be determined by the following formula: NX AX SS = % Ts XTX P Where Ts equals tensile strength. Where T equals thickness of plate. Where P equals pitch of rivets in inches. Where A equals area of one rivet. Where N equals number of rivets. Where SS equals shearing strength of the rivets. Where % equals percentage of rivets compared to solid plate. 8052e2. Net section of plate.-26. The strength of the net section of plates compared to the solid plate shall be determined by the following formula: P-D =% P Where P equals pitch of rivet in inches. Where % equals percentage of net section compared to solid plate. 8052f2. Area of brace.-27. The area of an indirect or diagonal brace compared to the area of a direct brace required to support a given surface shall be determined by the following formula: X X L A M Where A equals sectional area of a diagonal brace. Where L equals length of diagonal brace. Where M equals line drawn at right angle to a boiler head. The area of a segment of the head to be stayed shall be the area enclosed by lines drawn three (3) inches from the shell and two (2) inches from the tubes. When a flat head has a manhole opening the flange of which is formed from the solid sheet and turned inward to a depth of not less than twice the thickness of the head, two (2) inches wide all around the manhole opening shall be deducted from the total manhole opening to be stayed. The following table gives the net area in square inches, of any segment of a head to be stayed: Height Diameter of Boiler. 16 tubes to shell 24" 30" 36" 42" 48" 54" 60" 66" 72" 78" 84" 90" 96" Area to be stayed in square inches. Diameter of Boiler. 24" 30" 36′′ 42′′ 48" 54" 60" 66" 72" 78" 84" 90" 96" Area to be stayed in square inches. 850 909 968 1024 1073 1120 1167 877 939 998 1053 1106 1157 1202 904 968 1030 1089 1145 1195 1243 930 997 1060 1120 1177 1232 1279 1028 1093 1157 1211 1270 1321 1056 1123 1187 1248 1305 1360 1084 1155 1221 1284 1347 1400 1115 1187 1255 1321 1382 1442 1218 1290 1358 1424 1480 1252 1324 1384 1459 1523 1286 1359 1433 1496 1561 1317 1394 1467 1538 1605 1430 1508 1575 1650 1465 1542 1617 1687 1500 1578 1655 1733 1536 1617 1695 1770 1654 1735 1816 1692 1775 1856 1810 1900 1857 1941 1984 2026 When an area is required that is not given in the above table, the following formula shall be used: .0608 Area of segment to be stayed in square inches. H equals distances from tubes to shell, minus five inches. 8052g2. Distance from center of rivet hole.-28. The distance from the center of rivet hole to edge of plate, (fire box seams excepted) shall not be less than one and one-half times the diameter of rivet hole. 8052h2. Right to drill.-29. Any boiler shall, when deemed necessary, be drilled at such points as the inspector may direct to determine the thickness of the material at these points and steam working pressure allowed shall be governed by such ascertained thickness and the general condition of the boiler. Second hand boilers. Such boilers provided for in section nine (9) of this act shall be allowed a factor of safety, the longitudinal joints of which are butt double strapped construction as age and condition warrant not less than six (6). Such boilers, the longitudinal joints of which are of lap riveted construction, shall be allowed a factor of safety as age and condition warrant not less than seven. The pressure may be still further reduced, if in the judgment of the inspector, or conditions warrant it. 805212. Prosecuting attorney, duties.-30. The prosecuting attorney of any county of this state is hereby required upon the request of the deputy inspector of the state bureau of inspection, his assistant deputies or any other person of full age, to commence and prosecute to a termination before any court of competent jurisdiction in the name of the state, actions or proceedings against any person, firm or corporation reported to him to have violated the provisions of this act. 8052j2. Penalty.-31. It shall be unlawful for any person, firm or corporation to operate any aforesaid boiler or boilers except as provided for in this act, and for violating any provision of sections 1 or 3 a fine of not less than ten dollars ($10.00) nor more than twentyfive dollars ($25.00) shall be assessed for each offense. Each day such violation or violations continue shall constitute a separate offense. Any person, firm or corporation failing to comply with any provision of sections 2, 5, 6, 12 or 19 of this act, or with any order issued by the deputy boiler inspector of the state bureau of inspection in accordance therewith, shall be fined not less than twenty-five dollars ($25.00) nor more than one hundred dollars ($100.00). |