NFPA 92 Section 4.5.1

NFPA 92 Section 4.4.2 / IBC 1010.1.3

This passes code. NFPA 92 Section 4.4.2 requires stairwell pressurization to achieve two performance criteria: (1) a minimum pressure differential of 0.05 inches w.c. across closed doors (this system achieves 0.08), and (2) sufficient airflow through open doors to prevent smoke migration. The 200 fpm velocity through open doorways is commonly accepted as the minimum to prevent smoke infiltration. IBC 1010.1.3 limits door-opening force to 30 lbf — the measured 20-28 lbf is within limits. The system achieves the delicate balance between maintaining enough pressure to exclude smoke while not overpressurizing to the point where doors cannot be opened.

NFPA 92 Section 4.4.2.1

NFPA 92 Section 4.4.2.1 requires multiple injection points for stairwells exceeding 8 stories in height. A single injection point creates excessive pressure at the top and insufficient pressure at the bottom, resulting in inability to open doors at upper floors and inadequate pressurization at lower floors. Multiple injection points every 2-3 floors are required for tall stairwells.

NFPA 92 Section 4.4.2.2 / IBC 1010.1.3

NFPA 92 Section 4.4.2.2 requires a means of pressure relief when all stairwell doors are closed. Without a barometric relief damper, the stairwell overpressurizes, making doors impossible to open (exceeding the 30 lbf maximum door-opening force per IBC 1010.1.3). Relief dampers maintain pressure within the required 0.05 to 0.10 inches w.c. differential.

NFPA 99 / ASSE 6010

Standard plumbing solder contains tin and sometimes other contaminants that are incompatible with oxygen systems. Medical gas piping must be brazed with BCuP-5 (silver-phosphorus-copper) alloy while purging with oil-free nitrogen.

NFPA 99 Section 5.1.10

This installation meets NFPA 99 requirements. Section 5.1.10 requires medical gas piping to be Type K or L seamless copper tubing specifically cleaned, capped, and sealed for medical gas service. BCuP-5 (silver-phosphorus) brazing alloy is an approved joining material. Nitrogen purging during brazing is required to prevent copper oxide formation inside the pipe, which could create particulate contamination in the gas stream. Pipe labeling at regular intervals with gas name, color coding, and flow direction arrows meets the identification requirements of NFPA 99 Section 5.1.11. This is a properly specified and executed medical gas installation.

NFPA 99 Section 5.1.10 / ASSE 6010

Standard silver brazing alloy (BAg series) contains flux and materials not suitable for oxygen service. Oxygen lines require phosphorus-copper-silver alloy (BCuP-5) applied without flux, as flux residue can contaminate the oxygen supply and is a combustion risk in an oxygen-enriched environment.