If Irvin Ortega doesn't show up for his scheduled shift at an Oakland McDonald's this week, it will mark the third time in the past year and a half that the 25-year-old has taken part in the nationwide fast food strikes .

"My manager was telling me, 'It's your right to go on strike. But if you can tell me when you will, I can cover your hours,'" said Ortega, an Oakland native. "I said, 'That defeats the purpose. The purpose is so you realize you need me and I'm a valuable worker.'"

Over the past two years, low-wage strikers like Ortega have helped fuel the national discussion on income inequality and have pressured lawmakers to consider raising the minimum wage. With the backing of the Service Employees International Union and a coalition of community groups, the workers are demanding a wage floor of $15 and a union.

Now, organizers with what's known as Fight for $15 say they're planning an escalation in the protests scheduled for Thursday. Though they couldn't offer estimates on how many workers are expected to take part, organizers said the strikes would take place in roughly 150 cities and include workers from McDonalds, Burger King, Wendys and KFC, among others.

Terrence Wise, a Burger King worker and a member of the coalition's organizing committee, said in a statement that workers are ready to get arrested in acts of civil disobedience.

"Thirteen hundred workers unanimously adopted a resolution at our convention in July to do whatever it takes to win $15 an hour and union rights, including participating in non-violent, peaceful protests in the tradition of the civil rights movement," Wise said. "On Thursday, we are prepared to take arrests to show our commitment to the growing Fight for $15."

The Fight for $15 campaign got a boost on Monday during President Barack Obama 's Labor Day speech. Speaking to a crowd of union members and supporters in Milwaukee, Obama argued that the risks taken by fast-food workers underscore the need to raise the minimum wage.

"All across the country right now theres a national movement going on made up of fast-food workers organizing to lift wages so they can provide for their families with pride and dignity," Obama said. "There is no denying a simple truth. America deserves a raise."

The president is backing a Democratic proposal to hike the federal minimum wage to $10.10 per hour and tie it to an inflation index, though congressional Republicans have blocked the proposal from moving forward.

In a nod to one of the fast-food workers' explicit demands, Obama also made a rare call for more collective bargaining in the U.S. economy, arguing that union membership would raise standards for lower-wage service workers.

"You know what? If I were looking for a job that lets me build some security for my family, Id join a union," Obama said. "If I were busting my butt in the service industry and wanted an honest days pay for an honest days work, Id join a union."

With a few exceptions, the fast food industry is a union-free world. Coordinated by SEIU and its allies, the Fight for $15 campaign signifies organized labor's most concerted and sustained effort to draw fast-food workers into its ranks.

The strikes and protests have been credited with helping to push through minimum wage raises on the local and state level over the past year. They've also brought a stream of negative publicity to fast food companies like McDonald's, which acknowledged in its annual report earlier this year that the "increasing public focus" on income inequality could pressure it to raise wages.

Although the campaign hasn't yet led to union membership for Ortega, the three-year McDonald's veteran said taking part in the strikes has changed the way he sees his job. He has a 3-year-old daughter, and said he now earns $9 per hour, the California minimum wage. Unhappy with his pay, Ortega said the protests have given him and his colleagues an outlet to voice their dissatisfaction, as well as the hope that working standards in the industry will rise.

"I felt like my manager gave me more respect," Ortega said of the strikes. "And that's something I want to give to my other coworkers. I know people who've been working [in fast food] for 15 years. You can show them you're not happy."