The Charity Commission found that charities working in areas such as human rights, religious harmony and racial harmony were the most likely to report being affected.
The standards cover six areas: violence prevention and reduction, sexual safety, tackling racism, flexible working, line management, and health and wellbeing support.
A survey of more than 1,600 care workers conducted by the union in May and June found that 52% had been subjected to attacks while carrying out their roles.
New research urges NHS organisations to focus on the period after violent incidents to better protect staff wellbeing and improve retention.
Caitroina McCusker, Northern Ireland market senior partner at PwC UK, said: “Together, we can create safer, more inclusive workplaces and contribute to a Northern Ireland where everyone can thrive.”
Martin Gannon said: “By signing this Charter, we're making a clear and public commitment to protect our staff and ensure they feel safe and supported in their roles."
In a survey of more than 1,700 GMB care workers, 52% said they had been physically assaulted at work.