Document label for 10 Cortlandt Street

NYC 9/11 Public Portal Document

Hillmann Environmental Group. LLC

24°' Floor <0.0040 0.01 25i° Floor <0.0042 0.01 26"' Floor <0.0041 0.01 27`" Floor <0.0041 0.01 28°i Floor <0.0042 0.01 29 Floor <0.0046 0.01 30'" Floor <0.0045 0.01 31" Floor <0.0041 0.01 32nd Floor <0.0041 0.01 33'd Floor <0.0042 0.01 34' Floor <0.0042 0.01 35Ib Floor <0.0042 0.01

SECTION 4— DISCUSSION

While on site, 1-fillmann performed various types of air sampling and observed work conditions.

4.1 Temperature

The American Society of Heating. Refrigeration and Air-conditioning Engineers (ASHRAE) recommends temperatures be kept between 66°F and 76°F. In the occupied space, temperatures ranged from 67°F to 74°F and were within the recommended range.

4.2 Relative Humidity

ASHRAE recommends relative humidity range between 30% and 60%. Relative humidity levels in the subject space ranged from 36% to 50% and were within the recommended range in all areas.

4.3 Carbon Dioxide

ASHRAE recommends carbon dioxide levels remain below an outdoor reading plus 700 ppm. Since the outdoor reading was 390 ppm, the recommended limit is 1090 ppm. Carbon dioxide levels in the subject space ranged from 748 ppm to 506 ppm. Carbon dioxide levels were below the recommended limit.

4.4 Carbon Monoxide

Carbon monoxide, a colorless, odorless gas, is a by-product of incomplete combustion. Carbon monoxide combines with hemoglobin in the blood to cause carboxyhemoglobin poisoning. Carbon monoxide can be released by many different sources such as: motor vehicle exhaust (intakes for the ventilation system located near a loading dock), tobacco smoke, and cracked exchangers on gas-fired heating appliances. The standards for Carbon Monoxide are the American Conference of Governmental Industrial Hygienists (ACG1H) Threshold Limit Value (TLV) of 35 ppm, the Occupational Satiny and Health Administration (OSHA) Permissible Exposure Level (PEL) of 35 ppm, and the Environmental Protection Agency (EPA) National Ambient Air Quality Standard (NAAQS) of 9 ppm. Carbon monoxide levels measured in the occupied areas ranged from 0 ppm to I ppm and were below the recommended range.

22 Cortlandt Street/New York, NY/Projecl Number Y2-1458 Page 21

NYC-WTC 000126282