From: Krivo, Stan

Sent: Monday, June 24, 2013 2:19 PM

To: Shepherd, Lorinda Subject: FW: Statoil Support Vessels pictures
Attachments: Peyton_Candies.jpg; Otto_Candies

- Claire.pdf; Otto_Candies

- Peyton.pdf; Gulf_Tiger_OSV.pdf; Graham_Gulf

- Sybil_Graham.pdf; Maersk Developer Sample VOLUME sources.xlsx

Lori,

This is for your information and project files. ...sjk

From: Bart Brashers [ mailto:bbrashers@environcorp.com ]
Sent: Monday, June 17, 2013 8:14 PM
To: Krivo , Stan Subject: Statoil Support Vessels pictures

Stan,

Enclosed are a sampling of boats we looked at to find a typical crew boat and OSV. I believe the Peyton and the Otto are pretty much identical, just different years.

The Sybil is 10.7m wide, the Ca ndies are 18.3m wide, and the Tiger is in the middle at 16.5m wide. If we average the Sybil and the Candies we get 14.5m. This would give a conservative Sigma

- Y of 6.744m

.

For Simga

- Z, it’s a bit harder because they don’t give the height of pilothouse a bove the waterline. You can see from the JPG enclosed that the exhaust ports are actually angled back by 45°, but clearly near the top of the pilothouse. Estimating the height of the pilothouse on the Sybil, it looks like at least 25 feet (at least 4 tim es as tall as the person I think I see on deck). For the Candies, it’s about the same height above water as the width of the boat. So the average of 18m and 25ft is 12.81m. Divide that by 2.15 and we get a conservative Sigma

- Z of 5.96m

. This also gives a volume source Height of 6.41m

. In reality, the turbulence from the ships’ wake, along with the buoyant plume rise of the exhaust, should make sigma

- z be larger than that, but we’ll test this conservativism and see if it works.

(I also set the Forkli ft’s Sigma

- Z to be based on 6 ft, just in case you also thought that 10 was too generous.)

I take the sum of the emission rates for each pollutant (SO2, SO4, etc.) over both boats, and divide by
the number of volume sources used. I’ll try with both 10 an d 100 volume sources overnight, and see what we get.

I’ve also enclosed a sample spreadsheet that shows how I calculated the emission rate from each

VOLUME source. Basically, I sum the total OSV + Crewboat emissions, then divide by the number of

VOLUME s ources used to represent those emissions. I removed the links to other sheets (which make the XLSX file huge) and did a “paste values” instead.This is equivalent the phrase in the ISC manual (last sentence of page 1

- 48) that says “The doubling of

[sigma

- y] by the user in the approximate line

- source representation in Figure 1

- 8(b) is offset by the fact that the emission rates for the individual volume sources are also doubled by the user.” The number of VOLUME sources is cut in half, so that

Individual VOLUME source emissions = TOTAL emissions / Number of volume sources

So if you double the denominator, you have doubled the magnitude of the individual VOLUME source.

Bart

Bart Brashers | Atmospheric Scientist Senior Manager, ENVIRON International Corporation
19020 33 rd Ave W Ste 310 | Lynnwood WA 98036 T: +1 425

- 412

- 1812 | F: +1 425

- 412

- 1840 | M: +1 206

- 550

- 2606 bbrashers@environcorp.com



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