SPECIFICATIONS. 367 



GENERAL SPECIFICATIONS FOR STEEL WATER AND OIL TANKS.* 



1. Scope of Specifications. These specifications are intended for steel tanks requiring plates 

 not more than f in. thick. 



2. Quality of Metal. The metal in these tanks shall be open-hearth steel. The steel shall 

 conform in physical and chemical properties to the specifications of this Association for steel 



3. Loading. The weight of water shall be assumed to be 63 lb., crude oil 56 lb., and creosote 

 oil 66 lb. per cu. ft. Wind pressure, acting in any direction, shall be assumed to be, in pounds, 

 30 times the product of the height by two-thirds of the diameter of the tank in feet. 



A. Unit Stresses. Unit stresses shall not exceed the following: 



(a) Tension in plates, 15,000 lb. per sq. in. on net section. 



(b) Shear in plates, 12,000 lb. per sq. in. on net section. 



(c) Shear on rivets, 12,000 lb. per sq. in. on net section. 



(d) Bearing pressure on field rivets, 20,000 lb. per sq. in. 



5. Cylindrical Rings. Plates forming the shell of the tank shall be cylindrical am/ 01 aifferent 

 diameters, in and out, from course to course. 



6. Workmanship. All workmanship shall be first-class. All plates shall be beveled on all 

 edges for caulking after being punched. The punching shall be from the surface to be in contact. 

 The plates shall be formed cold to exact form .after punching and beveling. All rivet holes shall 

 be accurately spaced. Drift pins shall be used only for bringing the parts together. They shall 

 not be driven with enough force to deform the metal about the holes. Power riveting and caulking 

 should be used. A heavy yoke or pneumatic bucker shall be used for power driven rivets. Rivet- 

 ing shall draw the joints to full and tight bearing. 



7. Caulking. The tank shall be made water or oil tight by caulking only. No foreign 

 substance shall be used in the joints. For water tanks, the caulking shall preferably be done 

 on the inside of tank and joint only; but for oil tanks the caulking should be done on both sides. 

 No form of caulking tool or work that injures the abutting plate shall be used. 



8. Minimum Thickness of Plates. The minimum thickness of plates in the cylindrical 

 part of the tank shall not be less than } in. and in flat bottoms not less than & in. In curved 

 bottoms the thickness of plate shall be not less than that of the lower plate in the cylindrical part. 



9. Horizontal and Radial Joints. Lap joints shall generally be used for horizontal seams 

 and splices and for radial seams in curved bottoms. 



10. Vertical Joints. For vertical seams and splices, lap joints shall be used with plates not 

 more than f in. thick. With thicker plates, double butt joints with inside and outside straps 

 shall generally be used. The edge of the plate in contact at the intersection of horizontal and 

 vertical lap joints shall be drawn out to a uniform taper and thin edge. 



11. Rivets, Rivet Holes, Punching and Pitch. For plates not more than f in. thick, f in. 

 rivets shall be used. For thicker plates, f in. rivets shall be used. The diameter of rivet holes 

 shall be -fa in. larger than the diameter of the rivets used. The punching shall conform to the 

 specifications of this Association for such work on steel bridges. A close pitch, with due regard 

 for thickness of plate and balanced stress between tension on plates and shear on rivets, is desirable 

 for caulking. 



12. Tank Support. If the tank is supported on a steel substructure, the latter shall con- 

 'form to the specifications of this Association for the manufacture and erection of steel bridges, 



except that allowance shall be made for wind pressure, but not for impact. 



13. Painting. In the shop the metal shall be cleaned of dirt, rust and scale and, except the 

 surfaces to be in contact in the joints of the tank, shall be given a shop coat of paint or metal 

 preservative selected and applied as specified by the company. 



After being completely erected, caulked and cleaned of dirt, rust and scale, all exposed metal 

 work shall be painted or treated with such coat or coats of paint or metal preservative as shall 

 be selected by the railway company. 



14. Plans and Specifications. Under these specifications and in conformity thereto the 

 railway company shall cause to be prepared or shall approve detailed plans and specifications for 

 such tanks, herein specified, as it shall construct. Such plans and specifications shall cover all 

 necessary tank auxiliaries. 



REFERENCES. Hazlehurst's " Towers and Tanks for Waterworks," second edition, 1904, 

 published by John Wiley & Sons, covers the design and construction of steel stand-pipes and steel 

 elevated tanks on steel towers, and supplements the data and discussion in this chapter. Con- 

 siderable data on the design and construction of stand-pipes and elevated tanks on towers for 

 railway service are given in the annual reports of the proceedings of the American Railway En- 

 gineering Association, particular reference is made to volume 1 1, part 2; volume 12, part 3, and 

 volume 13. 



* Adopted, Am. Ry. Eng. Assoc., Vol. 13, 1912. 



