Is the Viking Ø 80 big enough for a family fire?

The 31.5 in bowl is large for a backyard fire pit and comfortably seats four to six people around it. It takes standard firewood lengths without cutting down.

Yes. The finish is unpainted, so bare steel rusts when exposed to moisture. Many owners let it patina on purpose; others rub it with oil or store it covered to slow rust.

Does it come with a cover or spark screen?

No. A cover is not included, and no spark screen or cooking grate is listed. Budget for a cover if the pit stays outside.

How tall is it, and can I use it on a wooden deck?

The listed height is 15.75 in. That is low enough to sit around in chairs, but a wood deck needs a heat-resistant pad underneath and clearance from railings.

Not as sold. There is no grate or grill attachment listed, so it is a wood-burning fire pit rather than a grill. Adding a third-party grate over the bowl is possible.

How thick is the steel compared with other fire pits?

At 0.079 in it is on the thin side; many steel fire pits use 0.1 in or more. Thicker steel resists warping better, so handle this one gently and keep fires moderate.