5.2 Using Look-Up Tables, Dilution Charts, & Rotation Schedules

Using Look-Up Tables, Dilution Charts, & Rotation Schedules

In the daily operations of a USPS custodial worker, not all instructions are provided in simple sentences. Much of the vital information regarding chemical safety, equipment use, and shift assignments is presented in tabular format. Being able to read, interpret, and apply information from look-up tables, dilution charts, and rotation schedules is a critical skill tested on the Exam 916. This section will guide you through understanding these formats to ensure safety and efficiency.

Interpreting Chemical Dilution Charts

Cleaning chemicals are often shipped in highly concentrated forms to save on shipping costs and storage space. Using concentrated chemicals directly is dangerous and can damage surfaces. Custodians must use a dilution chart to determine the correct ratio of chemical to water.

Understanding Ratios

A dilution ratio is typically expressed as "Parts Chemical : Parts Water" (e.g., 1:64) or in ounces per gallon.

• 1:64 Ratio: 1 part chemical to 64 parts water. Since there are 128 ounces in a gallon, this equals 2 ounces of chemical per gallon of water.
• 1:12 Ratio: 1 part chemical to 12 parts water (approx. 10.6 ounces per gallon).

When reading a matrix chart for chemical mixing, you must cross-reference the product being used with the intended application. A single chemical might have different dilution requirements based on how dirty the surface is.

SDS and Chemical Compatibility

A critical component of using dilution charts is cross-referencing with Safety Data Sheets (SDS). The SDS provides vital information regarding the chemical properties, health hazards, and compatibility of cleaning agents. Never mix two different chemicals together (such as bleach and ammonia, which creates toxic chloramine gas) even if the dilution chart suggests they are used for similar purposes. Always use separate, clearly labeled spray bottles for different diluted solutions.

Additionally, secondary containers (like the spray bottles you fill from the chemical dispenser) must be properly labeled. An unlabeled bottle is an OSHA violation and a severe safety hazard, as another employee might misuse the product, leading to injury or damage to postal property.

Safety Rule: Always add the chemical to the water, not water to the chemical. Adding water directly to a concentrated chemical can cause a dangerous splash-back or rapid chemical reaction. Always wear the Personal Protective Equipment (PPE) specified on the Safety Data Sheet when mixing.

Following Shift Rotation Schedules

USPS processing plants and large post offices operate 24 hours a day, 365 days a year. Custodial coverage must align with this continuous operation. Shift rotation schedules are used to assign custodians to different shifts (Tour 1, Tour 2, Tour 3) and different days off.

• Tour 1: Night shift (e.g., 11:00 PM to 7:30 AM)
• Tour 2: Day shift (e.g., 7:00 AM to 3:30 PM)
• Tour 3: Evening shift (e.g., 3:00 PM to 11:30 PM)

A rotation schedule might show that you work Tour 2 for four weeks, then rotate to Tour 3. You must be able to look at a scheduling matrix, locate your name or employee ID, and determine your scheduled hours and rest days for any given week. Misreading a schedule can result in being AWOL (Absent Without Leave), which is a serious infraction.

When reading complex rotation schedules, pay close attention to your designated N/S (Non-Scheduled) days. These days may shift based on operational needs, especially around federal holidays or peak mailing seasons. Failing to interpret the schedule accurately can leave a facility understaffed during critical periods.

Managing Equipment Assignment Logs

In large facilities, expensive equipment like riding floor scrubbers, motorized sweepers, and high-speed burnishers are shared among the custodial staff. To track this equipment, facilities use assignment logs.

Using an Equipment Log

When you need a piece of equipment, you must check it out using the log. This involves finding the equipment ID, signing your name, noting the time out, and recording the equipment's condition. When you return it, you sign it back in and note any new damage or maintenance needed (e.g., "batteries need charging" or "squeegee blade torn").

If the log shows a floor scrubber is signed out to another employee, you must locate that employee or wait until it is returned; you cannot simply take another piece of equipment that is assigned elsewhere or out of service for maintenance.

Utilizing Inventory Requisition Sheets

Custodians are responsible for ensuring that restrooms, breakrooms, and workrooms are adequately stocked with supplies (paper towels, toilet paper, soap, trash liners). When supplies run low in your custodial closet, you must use an inventory requisition sheet to request more items from the main supply room.

A requisition table typically requires you to provide the Item Number, Description, Quantity Requested, and the Storage Area it is for. You must accurately look up the item numbers; requesting "Item #405" instead of "Item #450" might result in receiving industrial floor wax instead of hand soap.

Best Practices for Requisitions

• Anticipate needs: Do not wait until you are completely out of a product to request more.
• Follow units of measure: Pay attention to whether the chart specifies "Each", "Box", or "Case". Requesting "2 Cases" when you only need "2 Each" wastes space and facility resources.

By mastering these look-up tables and charts, you prove your ability to follow complex written instructions, maintain safety standards, and manage resources effectively—all crucial elements of passing the Exam 916 and succeeding on the job.