- forms (120 sheets) were placed inside the chamber for each test. Sheets were separated at the rate of 1 form or 4 sheets/min. After the 30-min separating procedure, the sheets were left exposed in the chamber for the rest of the 1-hr sampling process. The sampling flow rate was approximately 0.5 L/min. The maximum average formaldehyde concentration for 3 replicates was 0.37 ppm after 1 hr.
- Ventilation studies: Four types of paper were used to examine the effect of ventilation on the concentration of formaldehyde in the chamber air. For each test, 120 sheets of paper were placed inside the chamber. Page turning, ventilation, and sampling all began at time zero. Pages were turned at the rate of 4 sheets/min for 30 min and were left exposed in the chamber for the final 30 mins. Ventilation and sampling were continuous for the full hr. Ventilation was simulated by forcing compressed air into the chamber and allowing the air to flow out through a hole in the rear of the chamber. The ventilation rate was approximately 0.5 air change/hr for CB–15 blue, CB–15 black, and self-contained-17 black. This rate was obtained by using a flow rate of 2.6 to 2.9 L/min. Ventilation for SC–14 black was approximately 1 air change/hr, obtained by using a flow rate of 5.1 L/min. The sampling flow rate was approximately 0.5 L/min. The results are shown in Table 3–9.
The release of formaldehyde for the combined marking and separating activity demonstrated a value between the maximum concentrations for either activity measured alone. The maximum average formaldehyde concentration was 0.402 ppm after 1 hr for 2 replicates for marking and separating. Marking the forms (maximum average formaldehyde concentration was 0.497 ppm after 1 hr for two replicates) had a greater impact on the release of formaldehyde than did separating them (maximum average formaldehyde concentration was 0.37 ppm after 1 hr for 3 replicates). The results permitted the investigator to develop a formula for predicting formaldehyde release in the office environment. Using the rate constants developed (the assumptions and calculations used were not provided), the investigator predicted a formaldehyde concentration of 0.033 ppm for a worker confined to a 1,000 ft3 room with no ventilation while marking and separating 30 four-ply forms/hr for 8 hr. This value is between the NIOSH recommended exposure limit (REL) of 0.016 ppm as an 8-hr time-weighted average (TWA) (with a 15-min ceiling limit of 0.1 ppm) and the OSHA permissible exposure limit (PEL) of 0.75 ppm as an 8-hr TWA (with a 2-ppm short-term exposure limit [STEL]).
3.3 Conclusions
Little consistency has been found in the literature when various investigators elected to perform air sampling analyses to assess potential exposure to CCP and its components as summarized in Table 3–1. The most frequently chosen analyte was formaldehyde. Of the seven studies reporting formaldehyde concentrations (summarized in Table 3–10), nearly all measurements exceeded the NIOSH REL of 0.016 ppm as an 8-hr TWA with a 15-min ceiling limit of 0.1 ppm [NIOSH 1981]; however, none exceeded the OSHA PEL of 0.75 ppm as an 8-hr TWA with a short-term exposure limit of 2 ppm [29 CFR 1910.1048]. Short-term exposures to this strong-smelling gas cause eye, nose, and throat irritation in some persons at concentrations of <1 ppm. At 5 to 30 ppm, formaldehyde causes cough, chest tightness, unusual heartbeat, and lower airway and chronic pulmonary obstruction [NIOSH 1996, 1998; NRC 1981]. The OSHA formaldehyde standard [29 CFR 1910.1048]
