N.Y. Comp. Codes R. & Regs. Tit. 12 §§ 4-13.4
Boilers of the wet-bottom type having an external width of over 36 inches shall have not less than 12 inches between the bottom of the boiler and floor line, with access for inspection. When the width is 36 inches or less, the distance between the bottom of the boiler and the floor line shall be not less than six inches, and when any part of the wet bottom is not farther from an outer edge than 12 inches it shall be not less than four inches. If handholes are located in the bottom area of the boiler, the bottom clearance for the boiler shall be not less than 12 inches regardless of width.
The minimum size of access doors used in a boiler setting shall be 12 inches by 16 inches, or equivalent area of which the least dimension is 11 inches.
Provision shall be made for the expansion and contraction of steam mains connected to boilers by providing substantial anchorage at suitable points, so that there shall be no undue strain transmitted to the boiler.
Feedwater or makeup water shall not be discharged directly into any part of a boiler exposed to the direct radiant heat from the fire. Feedwater shall not be introduced through the openings or connections used for the relief valve, the water column, or the water gage glass.
A heater for oil or other liquid harmful to boiler operations shall not be installed directly in the steam or water space within a boiler. Where an external-type heater for such service is used, means shall be provided to prevent the introduction into the boiler of oil or other liquid harmful to boiler operation.
All hot water heating systems shall be so installed that there will be no opportunity for the fluid-relief column to freeze or to be accidentally shut off.
If the system is equipped with an open expansion tank, an indoor overflow from the upper portion of the expansion tank shall be provided in addition to an open vent, the indoor flow to be carried within the building to a suitable plumbing fixture or to the basement. If the system is of the closed type, an airtight tank or other suitable air cushion shall be installed that will be consistent with the volume and capacity of the system. Provision shall be made for draining the tank without emptying the system.
When a stop valve is used in the supply pipe connection of a single boiler, there shall be one used in the return pipe connection unless a proper return loop is provided.
A stop valve shall be used in each supply and return pipe connection of two or more boilers connected to a common system. Provision shall be made for cleaning the interior of the return piping at or close to the boiler. When stop valves over two inches in size are used, they shall be of the outside-screw-and-yoke rising-spindle type or of such type as to indicate at a distance by the position of the spindle or other operating mechanism whether it is closed or open, and the wheel may be carried either on the yoke or attached to the spindle. If the valve is of the plug cock type, it must be fitted with a slow-opening mechanism and an indicating device, and the plug must be held in place by a guard or gland.
When stop valves are used, they shall be properly designated substantially as indicated by the following tags of metal or other durable material fastened to them:
| Supply Valve-Number () | Return Valve-Number () |
| Do Not Close Without Also | Do Not Close Without Also |
| Closing Return Valve- | Closing Supply Valve- |
| Number () | Number () |
The area of the opening shall be at least equal to the aggregate area based on the nominal diameters of all of the safety valves with which it connects. A screwed connection may be used for attaching a safety valve.
N.Y. Comp. Codes R. & Regs. Tit. 12 §§ 4-13.4