N.Y.C. Admin. Code § MC 1211: Section MC 1211: High-Pressure Steam and High Temperature Hot Water Piping Systems

1211.1 Scope.

The provisions of this section shall apply to high-pressure steam piping system, which is defined as a system operating at a steam pressure of more than 15 psi (103.4 kPa), and high temperature water intended for operation at pressures in excess of 160 psi (1103.2 kPa) and temperatures in excess of 250°F (121.1°C). For purposes of this section, loops, bends or offsets of the piping shall not be considered expansion joints.

1211.2 New systems.

For purposes of this section, the replacement of existing steam piping systems, the installation of a new system in existing buildings, as well as installations in buildings hereafter constructed, shall be considered to be new high-pressure steam piping systems. The following requirements are applicable:

1211.2.1 Design.

The design of new steam piping systems shall be conducted as follows:

1. The system shall be designed by an engineer. An application and plans shall be filed and the approval of the department obtained. The plans and application shall contain, but not be limited to, the following information:

1.1. Size and location of all steam piping.

1.2. The operating pressures and temperatures.

1.3. The location, type, specifications and details of all expansion joints.

1.4. The design, size, material and location of all anchors, guides and auxiliary steel, and the stresses thereon.

2. Systems using utility street steam shall be designed for a pressure of 200 psig (1379 kPa) and 413°F (211.7°C) up to and including the steam pressure reducing valve or valves which reduce the pressure of 90 psig (620.5 kPa) or below. For steam pressures between 90 psig (620.5 kPa) and 16 psig (110.3 kPa), the system shall be designed for 125 psig (861.8 kPa).

3. Steam distribution systems utilizing pressure reducing valves.

3.1. Safety Shutoff Valves (SSO) to protect downstream piping from overpressure shall be allowed in lieu of a safety relief valve vented to the outdoors as required by Section 1006.6.

3.2. SSO shall be designed to automatically close at or below the design pressure of the downstream piping system that is being protected, to provide positive shut-off against full upstream pressure. Manual reset shall be required to reopen the SSO.

3.3. SSO shall be designed in accordance with the Steam Distribution Utility System requirements of the utility company having jurisdiction and ASME B31.1.

4. Bellows expansion joints shall not be utilized on high pressure steam piping.

Exception: Bellows expansion joints shall be permitted for final connection to equipment where readily accessible for inspection and service and within Mechanical Equipment Rooms.

1211.2.2 Installation.

The installation of new steam piping systems shall be conducted as follows:

1. Installations, including any welding, shall be subject to special inspection.

2. Welders shall be qualified for all required pipe sizes, wall thicknesses and positions in accordance with the ASME Boiler and Pressure Vessel Code, Section IX. Requalification is required every five years or sooner if the commissioner has a specific reason to doubt a welder's ability to make acceptable welds.

3. Welder qualification testing shall be performed by an approved agency listed with the department, and the inspector witnessing the test shall be an authorized AWS Certified Welding Inspector. If the testing is by radiography, the test specimen shall be evaluated by personnel having a minimum radiography qualification of Level II in accordance with the ASNT, Document No. SNT-TC-1A, Supplement A. A successful radiographic test of a production weld made within the 6 months prior to requalification may be considered as an acceptable requalification test.

4. Copies of the certified welder qualification reports shall be maintained by the responsible welding agency and the company performing the welding, and shall be made available upon request to the department.

5. No reports from any welding inspection agency shall be accepted unless such agency has first requested and obtained approval from the department in accordance with rules of the department.

6. Pipe welding shall conform to the following:

6.1. All piping over 2 inches (50.8 mm) shall be butt-welded. Piping 2 inches (50.8 mm) and under may be socket-welded or threaded, providing Schedule 80 piping is utilized.

6.2. Threaded piping may continue to be used for existing construction in sizes of 6 inches (152.4 mm) and under.

6.3. Where welding is not feasible, the commissioner may allow an acceptable alternative.

7. Radiographic examination, when required, shall be performed on butt-welds in accordance with ASME B31.1 based on the piping system design pressure and shall be as follows:

Piping System Design Pressure

Percentage

90 psig (620.5 kPa) or below

Not Required

91 psig (627.4 kPa) to 150 psig (1034.2 kPa)

10 at Random

Over 150 psig (1034.2 kPa)

100

However, if, in the opinion of the engineer responsible for special inspection, radiographic examination is not required for piping at pressure between 90 psig (620.5 kPa) and 150 psig (1034.2 kPa), the engineer shall so specify in writing, and the final report on the installation may omit the foregoing, and be predicated on all of the other requirements noted in this section, and a hydrostatic test.

1211.2.3 Testing.

Hydrostatic testing shall be conducted on the completed installation at 150 percent of the design pressure for all piping pressure. Where the changes in an existing steam system involve less than 30 percent of the piping in the system, the testing may be in accordance with ASME B31.1.

1211.2.4 Relocation.

The commissioner, where deemed necessary, shall require the replacement or relocation of any expansion joints, guides or anchors. The commissioner shall cause the expansion joints in potentially hazardous locations, such as those that are located adjacent to tenant occupied spaces, to be relocated, unless means exist or are provided for eliminating the hazard.

1211.3 Existing systems.

Existing steam piping systems shall be in accordance with Sections 1211.3.1 through 1211.3.2. Upon the completion of a new high-pressure steam piping system and department approval of same, the rules relating to maintenance requirements and the keeping of records for existing high-pressure steam piping systems shall apply.

1211.3.1 Maintenance inspections.

Expansion joints, anchorage and guides shall be inspected as follows:

1. Expansion joints shall be visually inspected monthly.

2. The anchorage and guides shall be visually inspected annually. Exposure of the structural attachments to the buildings of the anchorages or guides shall not be required.

3. A record of such inspections shall be kept by the person in charge of the mechanical equipment of the building or other qualified person designated by the owner and acceptable to the commissioner. The records shall be available at the premises and subject to inspection by the commissioner.

1211.3.2 Work approval.

No joint, anchorage or guides shall be repaired, replaced or relocated without a work permit issued by the department. The application for the permit shall contain all pertinent information and shall be filed by an engineer knowledgeable as to high-pressure steam piping systems. The engineer shall be responsible for the special inspection of the proposed work in accordance with the approved application. This provision shall not apply to the repacking of a slip or ball joint; however, records of such repacking shall be kept in the inspection records as provided in Section 1211.3.1, Item 3. When, in the opinion of the engineer, the requirement for prior department approval would create an imminent health or safety hazard, the engineer may permit the work to proceed without prior approval. In such cases, the engineer shall, prior to the repair, replacement or relocation, notify by telephone the borough commissioner of the borough in which the building is located; and, if the emergency occurs at other than normal working hours, he or she shall notify the department in a manner prescribed by the commissioner. This shall be followed by the filing of the application for department approval as specified in Section 28-105.4.1 of the Administrative Code.