Were conditions in the Triangle Shirtwaist Factory usual for factories at the time?

Yes, they were

Explanation:

Triangle Shirtwaist Factory made the news after a fire incident that resulted in 145 workers death.  After investigations, it's found that the fire actually caused by the owner's neglect to provide safety measurements in the workplace.

This event occurred in 1911. At that time, the government hasn't passed the laws needed to force the employers to follow a strict regulation to maintain workplace's safety. Maintain this regulation tend to cost the company a lot of money. This is why The majority of factories in that time did not follow a safety standard.