November 3, 2026
Safety Focus
Part 2 of 4: PPE Fundamentals
The right PPE starts with the hazard, not the catalog. Walk the day in the order the work happens and ask what each step can do to you.
Setting up and handling pipe. Raising the mast, moving casing and drill pipe, working under the derrick: things fall, swing, and pinch. That is head and foot protection. On construction work, 1926.100(a) requires protective helmets where there is "a possible danger of head injury from impact, or from falling or flying objects, or from electrical shock and burns."
Drilling and air returns. Cuttings and mud come off the table and out of the discharge. That is eye protection. OSHA 1926.102(a)(1) requires appropriate eye or face protection against flying particles, molten metal, liquid chemicals, and harmful light. Where objects can fly, 1926.102(a)(2) requires side protection. Plain glasses without side shields do not meet it.
Mixing and placing grout. Cement and bentonite mean dust, splashes, and wet cement on skin. Arizona's OSHA program warns that wet concrete is alkaline and that continuous skin contact can burn. That is eyes, hands, and skin. Friday's Health Focus covers what cement does to an eye.
Cutting and welding casing. Sparks, slag, and arc light. Eye and face protection with the right filter shade; 1926.102(c)(1) points to Table E-1 as the guide for shade numbers.
Tongs, wire rope, and tools. Cuts, pinches, and abrasion all shift long. That is hands.
Hands are the odd one out in construction PPE. There is no stand-alone construction standard for gloves, so they fall under the general rule in 1926.95: protection wherever a hazard requires it. Match the glove to the hazard (cut, chemical, abrasion), because one glove rarely does everything.
This list is a crew practice for walking a job, not an OSHA checklist. Your site, your hazards, and your company program decide the final list.
Key Takeaways:
• Pick PPE by walking the job step by step and naming the hazard at each step.
• Where objects can fly, eye protection needs side protection (1926.102(a)(2)).
• Gloves fall under the general PPE rule; match the glove to the hazard.
Sources:
• OSHA: 29 CFR 1926.100, Head Protection
• Arizona Division of Occupational Safety and Health: Portland Cement Hazards
Knowledge Share
Part 2 of 4: Slot Selection and Open Area
Formula Spotlight: Reading the Slot Off the Curve
Yesterday's rule: for our Week 11 sample (Cu about 3.3), A100-20 says the slot retains 40 to 50 percent of the sample. Here is how to turn that into a number.
Formula Spotlight: reading the slot. On a percent-passing curve, percent passing = 100 minus percent retained. So find the passing line, then read the grain size where the curve crosses it.
• Retain 40 percent: read at 60 percent passing. That is the #30 sieve, .023".
• Retain 50 percent: read at 50 percent passing. Interpolating between the #40 (.0165") and #30 (.0234") sieves gives about .019".
The slot range is about .019" to .023". Screen slots are commonly named by their opening, so a .020" opening is a 20-slot, and it sits in that range. If the water is corrosive or you doubt the sample, A100 adds 10 percent to the retention. That shifts this sample to about .016" to .019".
Percent open area = (total slot opening area ÷ outside surface area of the screen) × 100.
Here is where this newsletter takes a position, and the standard backs it. A100-20 Section 4.5.5.3 says the open area of most commercial screens is normally sufficient for satisfactory performance, and that well capacity does not directly correspond to differences in open area. Its informational appendix shows why open area makes a poor sizing rule on its own: depending on the open area and velocity assumed, its examples swing the design screen length from 3 feet to 630 feet. Pick the slot for the filter pack, and the filter pack for the formation. Efficiency, longevity, and durability come from those choices, not from maximizing open area.
The conventional view, because it may be on your exam: many designers have limited screen entrance velocity to 0.1 ft/s. A100's foreword says no single velocity criterion works without looking at the aquifer, and the standard does not recommend designing on velocity. Week 14 takes that on in full.
What to check before you order:
• Read the slot at (100 minus percent retained) percent passing.
• Add 10 percent retention for corrosive water or a sample you do not trust.
• Choose the slot for the formation first; do not pick a screen for its open area.
Sources:
• AWWA: ANSI/AWWA A100-20, Water Wells
Recommended Print References:
• Hydraulics of Wells: American Society of Civil Engineers
• Handbook of Ground Water Development- Roscoe Moss Company
• Groundwater & Wells, Third Edition- Edited by Robert J. Sterrett, Johnson Screens
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