Subpart T
Openings cut in a floor for disposal of materials may not exceed 25 percent of the aggregate of the total floor area unless the lateral supports of the removed flooring remain in place. See 1926.853.
The 25 percent limit applies to the aggregate total area of the individual floor where openings are cut (i.e., calculate opening area as a percentage of that floor's total area). The standard language is in 1926.853.
If the lateral supports for the removed flooring remain in place, you are not limited by the 25 percent maximum — the intent is that the structural support must be preserved so the floor can still safely carry loads. In other words, larger openings are permitted only when the remaining lateral supports continue to provide adequate structural support. See 1926.853.
Floors that are weakened or otherwise made unsafe by demolition operations must be shored so they can safely carry the intended imposed load from those operations. That means install structural supports (shoring) adequate for the loads expected from workers, equipment, and stored materials. See 1926.853.
The employer is responsible for ensuring floors are shored when weakened and that openings comply with the size limitation — employers must assess hazards and provide a safe workplace. OSHA guidance on employer hazard assessment obligations can help clarify how to identify and control these risks; see the PPE hazard assessment discussion in the letter at https://www.osha.gov/laws-regs/standardinterpretations/2024-03-28 and 1926.853.
Add the area of all openings on that floor and compare the sum to the floor's total area; total opening area must not exceed 25 percent of the floor's aggregate area unless lateral supports remain in place. Conduct this calculation before cutting openings as part of your demolition planning and hazard assessment. See 1926.853 and OSHA guidance on workplace hazard assessments at https://www.osha.gov/laws-regs/standardinterpretations/2024-03-28 for planning practices.
No — the only exception in the text of the standard is when the lateral supports of the removed flooring remain in place; temporary guarding or covers do not change the 25 percent limitation. Regardless, if the floor is weakened by cutting openings, you must shore it to carry the intended imposed load. See 1926.853.
The intended imposed load includes the weight of demolition workers, tools and equipment, stored materials, and any dynamic loads produced by demolition activities; shoring must be designed to safely carry those anticipated loads. Use your workplace hazard assessment to identify those loads and design appropriate shoring. See 1926.853 and OSHA's hazard-assessment guidance at https://www.osha.gov/laws-regs/standardinterpretations/2024-03-28 for employer responsibilities.
Yes — the structural requirements of 1926.853 still apply for demolition-related openings, and when asbestos-containing building material (ACBM) is involved, asbestos-specific rules in 29 CFR 1926.1101 also apply. OSHA explains that demolition involving ACBM is covered by the construction asbestos standard in the letter at https://www.osha.gov/laws-regs/standardinterpretations/2024-11-14, so you must comply with both the floor-opening and asbestos work requirements.
1926.853 does not prescribe specific written records or inspection forms; however, employers must assess hazards and ensure work is performed safely, which commonly includes documented inspections and engineering checks for shoring and structural integrity. OSHA's discussion of employer hazard assessment and written certification requirements can inform good practice; see 1926.853 and OSHA's hazard assessment guidance at https://www.osha.gov/laws-regs/standardinterpretations/2024-03-28.
You must either keep the lateral supports of the removed flooring in place so the exception applies or shore the floor adequately to carry the intended demolition loads before creating an opening that would exceed 25 percent of the floor area. Additionally, perform a hazard assessment and engineer or design the chute and shoring to handle loads safely. See 1926.853 and OSHA hazard-assessment guidance at https://www.osha.gov/laws-regs/standardinterpretations/2024-03-28.
The standard applies to demolition operations that create openings in floors; that includes full demolition and partial demolition or renovation activities when openings are cut for disposal of materials. Employers must follow the 25 percent rule and shore weakened floors as required. See 1926.853.
While 1926.853 does not specify qualifications, shoring should be designed or approved by a competent person or qualified engineer knowledgeable in structural loads and demolition procedures; employers are responsible for ensuring competent assessment and controls. OSHA's guidance on employer hazard assessments explains that qualified evaluation is required when hazards are present. See 1926.853 and OSHA's hazard-assessment letter at https://www.osha.gov/laws-regs/standardinterpretations/2024-03-28.
Yes — if you leave or install lateral supports that perform the same structural function as the removed flooring (i.e., the lateral supports of the removed flooring remain in place or are replaced so the floor can safely carry loads), the 25 percent limit does not apply. Any alternative supports must be adequate to carry the intended imposed loads and should be planned and inspected. See 1926.853 and OSHA employer hazard-assessment guidance at https://www.osha.gov/laws-regs/standardinterpretations/2024-03-28.