218.104.22.168.4 Height of Vent and Separation
The height (H) and separation distance (D) of the vent pipe shall meet the criteria set forth in Table 222.214.171.124.4 for the combinations of maximum hydrogen flow rates and vent stack opening diameters listed. Alternative venting systems shall be allowed when in accordance with Section 2126.96.36.199.6.
CFM at NTPg
> 500 to ≤ 1,000
CFM at NTPg
|> 1,000 to ≤ 2,000 CFM at NTPg||> 2,000 to ≤ 5,000 CFM at NTPh||> 5,000 to ≤ 10,000 CFM at NTPh||> 10,000 to ≤ 20,000 CFM at NTPh|
- Minimum distance to property line is 1.25D.
- Designs seeking to achieve greater heights with commensurate reductions in separation distances shall be designed in accordance with accepted engineering practice.
- With this table personnel on the ground or on the building and/or equipment are exposed to a maximum of 1,500 Btu/hr. ft2,and are assumed to be provided with a means to escape to a shielded area within 3 minutes, including the case of a 30 ft./sec. wind.
- Designs seeking to achieve greater radiant exposures to noncombustible equipment shall be designed in accordance with accepted engineering practice.
- The analysis reflected in this table does not permit hydrogen air mixtures that would exceed one-half of the lower flammable limit (LFL) for hydrogen (2 percent by volume) at the building or equipment, including the case of a 30 ft./sec. wind.
- See Figure 2188.8.131.52.4.
- For vent pipe diameters up to and including 2 inches.
- For vent pipe diameters up to and including 3 inches.